xnu-123.5.tar.gz

[apple/xnu.git] / osfmk / ppc / cswtch.s

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */

#include <ppc/asm.h>
#include <ppc/proc_reg.h>
#include <cpus.h>
#include <assym.s>
#include <debug.h>
#include <mach/ppc/vm_param.h>
#include <ppc/exception.h>

#define FPVECDBG 0
#define GDDBG 0

        .text
        
/*
 * void     load_context(thread_t        thread)
 *
 * Load the context for the first kernel thread, and go.
 *
 * NOTE - if DEBUG is set, the former routine is a piece
 * of C capable of printing out debug info before calling the latter,
 * otherwise both entry points are identical.
 */

ENTRY2(load_context, Load_context, TAG_NO_FRAME_USED)

/*
 * Since this is the first thread, we came in on the interrupt
 * stack. The first thread never returns, so there is no need to
 * worry about saving its frame, hence we can reset the istackptr
 * back to the saved_state structure at it's top
 */
                        

/*
 * get new thread pointer and set it into the active_threads pointer
 *
 */
        
                        mfsprg  r6,0
                        lwz             r0,PP_INTSTACK_TOP_SS(r6)
                        lwz             r11,PP_CPU_DATA(r6)
                        stw             r0,PP_ISTACKPTR(r6)
                        stw             r3,CPU_ACTIVE_THREAD(r11)

/* Find the new stack and store it in active_stacks */
        
                        lwz             r12,PP_ACTIVE_STACKS(r6)
                        lwz             r1,THREAD_KERNEL_STACK(r3)
                        lwz             r9,THREAD_TOP_ACT(r3)                   /* Point to the active activation */
                        stw             r1,0(r12)
                        li              r0,0                                                    /* Clear a register */
                        lwz             r8,ACT_MACT_PCB(r9)                             /* Get the savearea used */
                        lwz             r10,SAVflags(r8)                                /* Get the savearea flags */
                        rlwinm  r7,r8,0,0,19                                    /* Switch to savearea base */
                        lwz             r11,SAVprev(r8)                                 /* Get the previous savearea */
                        mfmsr   r5                                                              /* Since we are passing control, get our MSR values */
                        lwz             r1,saver1(r8)                                   /* Load new stack pointer */
                        rlwinm  r10,r10,0,1,31                                  /* Remove the attached flag */
                        stw             r0,saver3(r8)                                   /* Make sure we pass in a 0 for the continuation */
                        lwz             r7,SACvrswap(r7)                                /* Get the translation from virtual to real */
                        stw             r0,FM_BACKPTR(r1)                               /* zero backptr */
                        stw             r5,savesrr1(r8)                                 /* Pass our MSR to the new guy */
                        stw             r10,SAVflags(r8)                                /* Pass back the flags */
                        xor             r3,r7,r8                                                /* Get the physical address of the new context save area */
                        stw             r11,ACT_MACT_PCB(r9)                    /* Unstack our savearea */
                        b               EXT(exception_exit)                             /* Go end it all... */
        
/* struct thread_shuttle *Switch_context(struct thread_shuttle   *old,
 *                                       void                    (*cont)(void),
 *                                       struct thread_shuttle   *new)
 *
 * Switch from one thread to another. If a continuation is supplied, then
 * we do not need to save callee save registers.
 *
 */

/* void Call_continuation( void (*continuation)(void),  vm_offset_t stack_ptr)
 */

ENTRY(Call_continuation, TAG_NO_FRAME_USED)
        mtlr    r3
        mr      r1, r4          /* Load new stack pointer */
        blr                     /* Jump to the continuation */

/*
 * Get the old kernel stack, and store into the thread structure.
 * See if a continuation is supplied, and skip state save if so.
 * NB. Continuations are no longer used, so this test is omitted,
 * as should the second argument, but it is in generic code.
 * We always save state. This does not hurt even if continuations
 * are put back in.
 */

/*                      Context switches are double jumps.  We pass the following to the
 *                      context switch firmware call:
 *
 *                      R3  = switchee's savearea
 *                      R4  = old thread
 *                      R5  = new SRR0
 *                      R6  = new SRR1
 *
 *                      savesrr0 is set to go to switch_in
 *                      savesrr1 is set to uninterruptible with translation on
 */


ENTRY(Switch_context, TAG_NO_FRAME_USED)

                        mfsprg  r6,0                                                    /* Get the per_proc block */
                        lwz             r12,PP_ACTIVE_STACKS(r6)
#if DEBUG
                        lwz             r11,PP_ISTACKPTR(r6)                    ; (DEBUG/TRACE) make sure we are not
                        mr.             r11,r11                                                 ; (DEBUG/TRACE) on the interrupt
                        bne+    notonintstack                                   ; (DEBUG/TRACE) stack
                        BREAKPOINT_TRAP
notonintstack:
#endif  
                        stw             r4,THREAD_CONTINUATION(r3)
                        cmpwi   cr1,r4,0                                                /* used waaaay down below */
                        lwz             r11,0(r12)
                        stw             r11,THREAD_KERNEL_STACK(r3)
/*
 * Make the new thread the current thread.
 */
        
                        lwz             r11,PP_CPU_DATA(r6)
                        stw             r5,     CPU_ACTIVE_THREAD(r11)
                        
                        lwz             r11,THREAD_KERNEL_STACK(r5)
                
                        lwz             r5,THREAD_TOP_ACT(r5)
                        lwz             r10,PP_ACTIVE_STACKS(r6)
                        lwz             r7,CTHREAD_SELF(r5)                             ; Pick up the user assist word
                        lwz             r8,ACT_MACT_PCB(r5)                             /* Get the PCB for the new guy */
                
                        stw             r11,0(r10)                                              ; Save the kernel stack address
                        stw             r7,UAW(r6)                                              ; Save the assist word for the "ultra fast path"
                
                        lwz             r7,ACT_MACT_SPF(r5)                             ; Get the special flags
                        
                        lwz             r10,ACT_KLOADED(r5)
                        li              r0,0
                        cmpwi   cr0,r10,0
                        lwz             r10,PP_ACTIVE_KLOADED(r6)
                        stw             r7,spcFlags(r6)                                 ; Set per_proc copy of the special flags
                        beq             cr0,.L_sw_ctx_not_kld
                
                        stw             r5,0(r10)
                        b               .L_sw_ctx_cont

.L_sw_ctx_not_kld:      
                        stw             r0,0(r10)                                               /* act_kloaded = 0 */

.L_sw_ctx_cont: 
                        lis             r10,hi16(EXT(trcWork))                  ; Get top of trace mask
                        rlwinm  r7,r8,0,0,19                                    /* Switch to savearea base */
                        ori             r10,r10,lo16(EXT(trcWork))              ; Get bottom of mask
                        lwz             r11,SAVprev(r8)                                 /* Get the previous of the switchee's savearea */
                        lwz             r10,traceMask(r10)                              ; Get the enabled traces
                        lis             r0,hi16(CutTrace)                               ; Trace FW call
                        mr.             r10,r10                                                 ; Any tracing going on?
                        ori             r0,r0,lo16(CutTrace)                    ; Trace FW call
                        beq+    cswNoTrc                                                ; No trace today, dude...
                        mr              r10,r3                                                  ; Save across trace
                        lwz             r2,THREAD_TOP_ACT(r3)                   ; Trace old activation
                        mr              r3,r11                                                  ; Trace prev savearea
                        sc                                                                              ; Cut trace entry of context switch
                        mr              r3,r10                                                  ; Restore
                        
cswNoTrc:       mfmsr   r6                                                              /* Get the MSR because the switched to thread should inherit it */
                        lwz             r7,SACvrswap(r7)                                /* Get the translation from virtual to real */
                        lis             r0,hi16(SwitchContextCall)              /* Top part of switch context */
                        lis             r9,hi16(EXT(switch_in))                 /* Get top of switch in routine */
                        stw             r11,ACT_MACT_PCB(r5)                    /* Dequeue the savearea we're switching to */

                        rlwinm  r6,r6,0,MSR_FP_BIT+1,MSR_FP_BIT-1       /* Turn off the FP */
                        ori             r9,r9,lo16(EXT(switch_in))              /* Bottom half of switch in */
                        lwz             r5,savesrr0(r8)                                 /* Set up the new SRR0 */
                        rlwinm  r6,r6,0,MSR_VEC_BIT+1,MSR_VEC_BIT-1     /* Turn off the vector */
                        mr              r4,r3                                                   /* Save our old thread to pass back */
                        stw             r9,savesrr0(r8)                                 /* Make us jump to the switch in routine */
                        li              r10,MSR_SUPERVISOR_INT_OFF              /* Get the switcher's MSR */
                        lwz             r9,SAVflags(r8)                                 /* Get the flags */
                        stw             r10,savesrr1(r8)                                /* Set up for switch in */
                        rlwinm  r9,r9,0,15,13                                   /* Reset the syscall flag */
                        ori             r0,r0,lo16(SwitchContextCall)   /* Bottom part of switch context */
                        rlwinm  r9,r9,0,1,31                                    /* Clear the attached flag */
                        xor             r3,r7,r8                                                /* Get the physical address of the new context save area */
                        stw             r9,SAVflags(r8)                                 /* Set the flags */
/* if blocking on continuation avoid saving state */
                        bne             cr1,1f
                        sc                                                                              /* Switch to the new context */
        
/*                      We come back here in the new thread context     
 *                      R4 was set to hold the old thread pointer, but switch_in will put it into
 *                      R3 where it belongs.
 */
                        blr                                                                             /* Jump into the new thread */
                
1:              stw             r5,savesrr0(r8)                                 /* go to real pc */
                stw             r4,saver3(r8)                                   /* must pass back old thread */
                b               EXT(exception_exit)                             /* blocking on continuation, avoid state save */



/*
 *                      All switched to threads come here first to clean up the old thread.
 *                      We need to do the following contortions because we need to keep
 *                      the LR clean. And because we need to manipulate the savearea chain
 *                      with translation on.  If we could, this should be done in lowmem_vectors
 *                      before translation is turned on.  But we can't, dang it!
 *
 *                      R3  = switcher's savearea
 *                      saver4  = old thread in switcher's save
 *                      saver5  = new SRR0 in switcher's save
 *                      saver6  = new SRR1 in switcher's save


 */
 
ENTRY(switch_in, TAG_NO_FRAME_USED)
                        
                        lwz             r4,saver4(r3)                                   /* Get the old thread */
                        li              r8,MSR_VM_OFF                                   /* Set to everything off */
                        lwz             r9,THREAD_TOP_ACT(r4)                   /* Get the switched from ACT */
                        lwz             r5,saver5(r3)                                   /* Get the srr0 value */
                        lwz             r10,ACT_MACT_PCB(r9)                    /* Get the top PCB on the old thread */
                        lwz             r6,saver6(r3)                                   /* Get the srr1 value */

                        stw             r3,ACT_MACT_PCB(r9)                             /* Put the new one on top */
                        stw             r10,SAVprev(r3)                                 /* Chain on the old one */

                        mr              r3,r4                                                   /* Pass back the old thread */

                        mtsrr0  r5                                                              /* Set return point */
                        mtsrr1  r6                                                              /* Set return MSR */
                        rfi                                                                             /* Jam... */
                        .long   0
                        .long   0
                        .long   0
                        .long   0
                        .long   0
                        .long   0
                        .long   0
                        .long   0


                        
/*
 * void fpu_save(void)
 *
 *              To do the floating point and VMX, we keep three thread pointers:  one
 *              to the current thread, one to the thread that has the floating point context
 *              loaded into the FPU registers, and one for the VMX owner.
 *
 *              Each of these threads has three PCB pointers.  The normal PCB, the FPU pcb,
 *              and the VMX pcb.  There is also a bit for each in the savearea flags.
 *              When we take an exception, or need to use the FPU/VMX in the kernel, we call
 *              this routine.  It checks to see if there is an owner thread for the facility.
 *              If so, it saves the facility's state information in the normal PCB. Then, it
 *              turns on the appropriate flag in the savearea to indicate that the state is
 *              in that particular savearea.  Also, the thread pointer for the owner in
 *              the per_processor block is cleared.  Note that we don't have to worry about the
 *              PCB pointers in the thread because whenever the state is loaded, the associated
 *              savearea is released and the pointer cleared.  This is done so that the facility
 *              context always migrates to the normal savearea/PCB.  This always insures that
 *              no more than 2 saveareas are used for a thread.
 *
 *              When the context is loaded into the facility, the associated PCB is released if
 *              its usage flags indicate that it is empty.  (Note that return from exception and
 *              context switch honor these flags and won't release a savearea if there is unrestored
 *              facility context.) The per_processor is set to point to the facility owner's
 *              thread and the associated PCB pointer within the thread is cleared because
 *              the PCB has been released.
 *
 *              Part of loading a context is to release the savearea.  If the savearea contains
 *              other context, the savearea cannot be released.  So, what we're left with is 
 *              that there will be no normal context savearea, but one for the as-not-yet
 *              restored facility savearea.  Again, when that context is reloaded, the PCB
 *              is released, and when it is again stored, it goes into the "normal" savearea.
 *
 *              So, what do we do when there is no general context, and we have some FPU/VMX
 *              state to save?  Heck if I know, but it happens when we switch threads when
 *              we shortcut system calls.  The question is: does the target thread carry the
 *              FPU/VMX context with it or not? Actually, it don't matter, not one little bit.
 *              If we are asked to save it, we gotta.  It's a really lousy way to do it, but
 *              short of starting over with FPUs, it's what's what.  Therefore, we'll
 *              allocate an FPU context save and attach it.  
 *
 *              Actually, it's not quite that simple:  since we aren't in 
 *              in interrupt handler context (that's only in fpu_switch) we can't use 
 *              quickfret to merge FPU into general context.  So, if there is an FPU
 *              savearea, we need to use that.  So what we do is:  if there is FPU context
 *              use that.  If there is a general context, then use that.  If neither, 
 *              allocate a savearea and make that the FPU context.
 *
 *              The next thing we have to do is to allow the kernel to use both the 
 *              floating point and Altivec.  It is not recommended, but there may be a
 *              good reason to do so. So, what we need to do is to treat each of the
 *              three types of context the same, by keeping a LIFO chain of states.
 *              We do have a problem with that in that there can be multiple levels of
 *              kernel context. For example, we are using floating point and we take a
 *              page fault, and somehow start using the FPU, and take another page fault,
 *              etc. 
 *
 *              Anyway, we will hope that we only reasonably use floating point and vectors in
 *              the kernel. And try to pack the context in as few saveareas as possible.
 *
 *              The way we keep these "levels" of floating point or vector context straight is
 *              to remember the top of the normal savearea chain when we activate the 
 *              facility when it is first used.  Then, when we save that context, this value
 *              is saved in its level field.
 *
 *              What the level concept gives us is a way to distinguish between multiple
 *              independent contexts under the same thread activation. Any time we take
 *              any kind of interruption (trap, system call, I/O interruption), we are,
 *              in effect, running with a different context even though we are in the 
 *              same thread. The top savearea address is used only as a marker. It does not
 *              point to any context associated with the float or vector context. For example,
 *              the top savearea pointer will always be 0 for the user context, because there 
 *              it it always last on the list.
 *
 *              As normal context is unstacked, the first facility context is checked and
 *              if there is a match, the facility savearea is released.  This is because we
 *              are returning to a level before the facility saved there was used. In effect,
 *              this allows us to unwind the facility context saveareas at different rates.
 *
 *              In conjunction with the current activation, these markers are also used to 
 *              determine the state of the facility enablement. Whenever the facility context is
 *              "live," i.e., loaded in the hardware registers and belonging to the currently
 *              running context, the facility is enabled before dispatch.
 *
 *              There is nothing special about using floating point or vector facilities,
 *              no preliminary saving, enabling, or disabling. You just use them.  The only exception
 *              is during context switching on an SMP system.  In this case, the context must
 *              be saved as there is no guarantee that the thread will resume on the same 
 *              processor. This is not a good thing, not at all.  
 *
 *              Whenever we switch out a thread with a dirty context, we always need to save it
 *              because it can wake up on a different processor.  However, once the context has
 *              been saved, we don't need to save it again until it gets dirty, nor do we need
 *              to reload it unless someone else's context has been loaded. To handle this
 *              optimization, we need 3 things.  We need to know what processor the saved context
 *              was last loaded on, whether the loaded context could be dirty, and if we've already 
 *              saved it.
 *
 *              Whenever the facility is enabled, the processor ID is saved in the activation. This
 *              will show which processor has dirty data. When a context switch occurs, the facility 
 *              contexts are saved, but are still remembered as live. The next time we need to
 *              context switch, we first check if the state is live, and if not, do no state
 *              saving.  Then we check if the state has already been save and if not, save it.
 *              The facility is always disabled on a context switch. On a UP, this save function
 *              does not occur.
 *              
 *              Whenever a facility unavailable interruption occurs, the current state is saved
 *              if it is live and unsaved.  However, if the live state is the same as the new
 *              one to be loaded, the processor ID is checked and if it is the current processor
 *              the state does not need to be loaded or saved. The facility is simply enabled.
 *              
 *              Once allocated, facility saveareas are not released until a return is made to a
 *              previous level. Once a facility has been enabled, there is no way to tell if
 *              it will ever be used again, but it is likely.  Therefore, discarding a savearea
 *              when its context is made live is extra overhead.  So, we don't do it, but we
 *              do mark the savearea contents as invalid.
 *              
 */

/*
;               The following is the actual way it is implemented.  It doesn't quite match
;               the above text. I need to go and fix that.
;
;       Context download (operates on owner's data):
;       
;       0)      enable facility
;       1)      if no owner exit to context restore
;       2)      if context processor != current processor exit to context restore
;       3)      if current activation == owner activation:
;               1)      if curr level == active level:
;                       1)      if top facility savearea exists:
;                               invalidate savearea by setting level to 1
;                       2)      enable facility for user
;                       3)      exit
;               
;               2) else go to 5
;       
;       4)      if curr level == active level:
;               1)      if top facility savearea exists:
;                       1)      if top save level == active level exit to context restore               
;       
;       5)      allocate savearea
;               1)      if there is a facility save and it is invalid, select it, and break
;               2)      scan normal list for free facility area, select if found, and break
;               3)      scan other facility for free save: select, if found, and break
;               4)      allocate a new save area
;       
;       6)      save context
;       7)      mark facility save with curr level
;       8)      if reusing cached savearea (case #1) exit to context restore
;       9)      set facility save backchain to facility top savearea
;       10)     set facility top to savearea
;       11)     exit to context restore
;       
;       
;       Context restore/upload (operates on current activation's data):
;       
;       1)      set current to activation
;       2)      set active level to current level
;       3)      set context processor to current processor
;       4)      if no facility savearea or top save level != curr level
;                       initialize facility registers to empty value
;       5)      else 
;               1)      load registers from savearea
;               2)      invalidate save area by setting level to 1
;               
;       6)      enable facility for user
;       7)      exit to interrupt return
;       
;       
;       Context save (operates on current activation's data; only used during context switch):
;                                (context switch always disables the facility)
;       
;       1)      if no owner exit
;       2)      if owner != current activation exit
;       3)      if context processor != current processor 
;               1)      clear owner
;               2)      exit
;               
;       4)      if facility top savearea level exists and == active level exit
;       5)      if curr level != active level exit
;       6)      allocate savearea
;               1)      if there is a facility save and it is invalid, select it, and break
;               2)      scan normal list for free facility area, select if found, and break
;               3)      scan other facility for free save: select, if found, and break
;               4)      allocate a new save area
;       7)      save context
;       8)      mark facility savearea with curr level
;       9)      if reusing cached savearea (case #1) exit
;       10)     set facility save backchain to facility top savearea
;       11)     set facility top to savearea
;       12)     exit
;       
;       
;       Exception exit (hw_exceptions):
;       
;       1)      disable return facility
;       2)      if returning savearea != active level 
;               1)      if owner != current activation exit
;               2)      if context processor != current processor:
;                       1)      clear owner
;                       2)      exit
;               
;               3)      if new level != active level exit
;               4)      enable return facility
;               5)      exit
;       
;       3)      if no facility savearea exit
;       4)      if top save level == active or top is invalid
;               1)      dequeue top facility savearea
;               2)      set active level to new top savearea's level
;               3)      release savearea
;               4)      if owner == current activation clear owner
;       5)      exit
;       
;       
;       
;       
;       if (owner == activation) && (curr level == active level)
;               && (activation processor == current processor) ::= context live
*/

ENTRY(fpu_save, TAG_NO_FRAME_USED)

                        mfmsr   r0                                              ; Get the MSR
                        rlwinm  r0,r0,0,MSR_FP_BIT+1,MSR_FP_BIT-1       ; Turn off floating point forever
                        rlwinm  r2,r0,0,MSR_EE_BIT+1,MSR_EE_BIT-1       ; But do interrupts only for now
                        ori             r2,r2,MASK(MSR_FP)              ; Enable the floating point feature for now also
                        mtmsr   r2                                              ; Set the MSR
                        isync
                
                        mfsprg  r6,0                                    ; Get the per_processor block 
                        lwz             r12,PP_FPU_THREAD(r6)   ; Get the thread that owns the FPU
#if FPVECDBG
                        mr              r7,r0                                   ; (TEST/DEBUG)
                        li              r4,0                                    ; (TEST/DEBUG)
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        mr.             r3,r12                                  ; (TEST/DEBUG)
                        li              r2,0x6F00                               ; (TEST/DEBUG)
                        li              r5,0                                    ; (TEST/DEBUG)
                        beq-    noowneryet                              ; (TEST/DEBUG)
                        lwz             r4,ACT_MACT_FPUlvl(r12) ; (TEST/DEBUG)
                        lwz             r5,ACT_MACT_FPU(r12)    ; (TEST/DEBUG)

noowneryet:     oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
                        mr              r0,r7                                   ; (TEST/DEBUG)
#endif  
                        mflr    r2                                              ; Save the return address
                        lwz             r10,PP_CPU_DATA(r6)             ; Get the CPU data pointer
                        lhz             r11,PP_CPU_NUMBER(r6)   ; Get our CPU number
                        
                        mr.             r12,r12                                 ; Anyone own the FPU?
                        
                        lwz             r10,CPU_ACTIVE_THREAD(r10)      ; Get the pointer to the active thread
                        
                        beq-    fsret                                   ; Nobody owns the FPU, no save required...
                        
                        lwz             r10,THREAD_TOP_ACT(r10) ; Now get the activation that is running
                        lwz             r9,ACT_MACT_FPUcpu(r12) ; Get the last CPU to use this context
                        
                        cmplw   r12,r10                                 ; Do we own the FPU?
                        cmplw   cr1,r9,r11                              ; Was the context for this processor? 
                        bne+    fsret                                   ; Facility belongs to some other activation...
                        li              r3,0                                    ; Assume we need a fix-me-up
                        beq-    cr1,fsgoodcpu                   ; Facility last used on this processor...
                        stw             r3,PP_FPU_THREAD(r6)    ; Clear owner because it was really on the other processor
                        b               fsret                                   ; Bail now with no save...
                        
fsgoodcpu:      lwz             r3,ACT_MACT_FPU(r12)    ; Get the current FPU savearea for the thread
                        lwz             r9,ACT_MACT_FPUlvl(r12) ; Get our current level indicator
                        
                        cmplwi  cr1,r3,0                                ; Have we ever saved this facility context?
                        beq-    cr1,fsneedone                   ; Never saved it, so we need an area...
                        
                        lwz             r8,SAVlvlfp(r3)                 ; Get the level this savearea is for
                        cmplwi  r8,1                                    ; See if it is a spare
                        cmplw   cr1,r9,r8                               ; Correct level?
                        beq+    fsusespare                              ; We have a spare to use...
                        beq-    cr1,fsret                               ; The current level is already saved, bail out...

fsneedone:      li              r3,0                                    ; Tell the routine to allocate an area if none found
                        bl              fpsrchsave                              ; Find a free savearea
                        
                        mfsprg  r6,0                                    ; Get back per_processor block
                        oris    r7,r7,hi16(SAVfpuvalid) ; Set the allocated bit
                        lwz             r12,PP_FPU_THREAD(r6)   ; Get back our thread
                        mtlr    r2                                              ; Restore return
                        lwz             r8,ACT_MACT_FPU(r12)    ; Get the current top floating point savearea
                        lwz             r9,ACT_MACT_FPUlvl(r12) ; Get our current level indicator again         
                        stw             r3,ACT_MACT_FPU(r12)    ; Set this as the latest FPU savearea for the thread
                        stw             r8,SAVprefp(r3)                 ; And then chain this in front
                        stw             r7,SAVflags(r3)                 ; Set the validity flags
                        stw             r12,SAVact(r3)                  ; Make sure we point to the right guy

fsusespare:     stw             r9,SAVlvlfp(r3)                 ; And set the level this savearea is for

;
;                       Save the current FPU state into the PCB of the thread that owns it.
; 

                        la              r11,savefp0(r3)                 ; Point to the 1st line
                        dcbz    0,r11                                   ; Allocate the first savearea line 
                        
                        la              r11,savefp4(r3)                 /* Point to the 2nd line */
                        stfd    f0,savefp0(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f1,savefp1(r3)
                        stfd    f2,savefp2(r3)
                        la              r11,savefp8(r3)                 /* Point to the 3rd line */
                        stfd    f3,savefp3(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f4,savefp4(r3)
                        stfd    f5,savefp5(r3)
                        stfd    f6,savefp6(r3)
                        la              r11,savefp12(r3)                /* Point to the 4th line */
                        stfd    f7,savefp7(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f8,savefp8(r3)
                        stfd    f9,savefp9(r3)
                        stfd    f10,savefp10(r3)
                        la              r11,savefp16(r3)                /* Point to the 5th line */
                        stfd    f11,savefp11(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f12,savefp12(r3)
                        stfd    f13,savefp13(r3)
                        stfd    f14,savefp14(r3)
                        la              r11,savefp20(r3)                /* Point to the 6th line */
                        stfd    f15,savefp15(r3)
                        stfd    f16,savefp16(r3)
                        stfd    f17,savefp17(r3)
                        stfd    f18,savefp18(r3)
                        la              r11,savefp24(r3)                /* Point to the 7th line */
                        stfd    f19,savefp19(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f20,savefp20(r3)
                        lwz             r10,liveFPSCR(r6)               ; Get the previously saved FPSCR
                        stfd    f21,savefp21(r3)
                        stfd    f22,savefp22(r3)
                        li              r9,0                                    ; Just clear this out 
                        la              r11,savefp28(r3)                /* Point to the 8th line */
                        stfd    f23,savefp23(r3)
                        dcbz    0,r11                                   /* allocate it */
                        stfd    f24,savefp24(r3)
                        stfd    f25,savefp25(r3)
                        stfd    f26,savefp26(r3)
                        stfd    f27,savefp27(r3)
                        stfd    f28,savefp28(r3)

;                       Note that we just save the FPSCR here for ease.  It is really already saved
;                       in the "normal" context area of the savearea.

                        stw             r9,savefpscrpad(r3)             ; Save the FPSCR pad
                        stw             r10,savefpscr(r3)               ; Save the FPSCR
                        
                        stfd    f29,savefp29(r3)
                        stfd    f30,savefp30(r3)
                        stfd    f31,savefp31(r3)
                        lfd     f0,savefp0(r3)                  ; We need to restore F0 because we used it      
                                                                                        ; to get the FPSCR
                                                                                        
#if 0
                        la              r9,savefp0(r3)                  ; (TEST/DEBUG)
                        la              r10,savefp31(r3)                ; (TEST/DEBUG)
                        
chkkillmedead:
                        lha             r8,0(r9)                                ; (TEST/DEBUG)
                        addi    r9,r9,8                                 ; (TEST/DEBUG)
                        cmpwi   r8,-8                                   ; (TEST/DEBUG)
                        cmplw   cr1,r9,r10                              ; (TEST/DEBUG)
                        bne+    dontkillmedead                  ; (TEST/DEBUG)
                        BREAKPOINT_TRAP                                 ; (TEST/DEBUG)

dontkillmedead:                                                         ; (TEST/DEBUG)
                        ble+    cr1,chkkillmedead               ; (TEST/DEBUG)
#endif

fsret:          mtmsr   r0                                              ; Put interrupts on if they were and floating point off
                        isync

                        blr

/*
 * fpu_switch()
 *
 * Entered to handle the floating-point unavailable exception and
 * switch fpu context
 *
 * This code is run in virtual address mode on with interrupts off.
 *
 * Upon exit, the code returns to the users context with the floating
 * point facility turned on.
 *
 * ENTRY:       VM switched ON
 *              Interrupts  OFF
 *              State is saved in savearea pointed to by R4.
 *                              All other registers are free.
 * 
 */

ENTRY(fpu_switch, TAG_NO_FRAME_USED)
#if DEBUG
#if GDDBG
                        mr              r7,r4                                   ; Save input parameter
                        lis             r3,hi16(EXT(fpu_trap_count))    ; Get address of FP trap counter
                        ori             r3,r3,lo16(EXT(fpu_trap_count)) ; Get address of FP trap counter
                        lwz             r1,0(r3)
                        lis             r5,hi16(EXT(GratefulDeb))       ; Point to top of display
                        ori             r5,r5,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        addi    r1,r1,1
                        mtlr    r5                                              ; Set link register
                        stw             r1,0(r3)
                        mr              r4,r1
                        li              r3,0
                        blrl                                                    ; Display count
                        mr              r4,r7                                   ; Restore the parameter
#else
                        lis             r3,hi16(EXT(fpu_trap_count))    ; Get address of FP trap counter
                        ori             r3,r3,lo16(EXT(fpu_trap_count)) ; Get address of FP trap counter
                        lwz             r1,0(r3)
                        addi    r1,r1,1
                        stw             r1,0(r3)
#endif
#endif /* DEBUG */

                        mfsprg  r6,0                                    ; Get the per_processor block
                        mfmsr   r19                                             ; Get the current MSR 
                        
                        lwz             r10,PP_CPU_DATA(r6)             ; Get the CPU data pointer
                        lwz             r12,PP_FPU_THREAD(r6)   ; Get the thread that owns the FPU
                        lwz             r10,CPU_ACTIVE_THREAD(r10)      ; Get the pointer to the active thread
                        ori             r19,r19,lo16(MASK(MSR_FP))      ; Enable the floating point feature
                        lwz             r17,THREAD_TOP_ACT(r10) ; Now get the activation that is running

;                       R12 has the "old" activation
;                       R17 has the "new" activation

#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F01                               ; (TEST/DEBUG)
                        mr              r3,r12                                  ; (TEST/DEBUG)
                        mr              r5,r17                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        mr.             r12,r12                                 ; See if there is any live FP status
                        
                        lhz             r18,PP_CPU_NUMBER(r6)   ; Get the current CPU, we will need it later
                        
                        mtmsr   r19                                             ; Enable floating point instructions
                        isync
                        
                        beq-    fsnosave                                ; No live context, so nothing to save...

                        lwz             r19,ACT_MACT_FPUcpu(r12)        ; Get the "old" active CPU
                        lwz             r15,ACT_MACT_PCB(r12)   ; Get the current level of the "old" one
                        cmplw   r18,r19                                 ; Check the CPU that the old context is live on
                        lwz             r14,ACT_MACT_FPU(r12)   ; Point to the top of the old context stack
                        bne-    fsnosave                                ; Context is not live if used on a different CPU...
                        lwz             r13,ACT_MACT_FPUlvl(r12)        ; Get the "old" active level
                        
;
;                       First, check to see if all we are doing is enabling because the
;                       "new" context is live.
;
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F02                               ; (TEST/DEBUG)
                        mr              r1,r15                                  ; (TEST/DEBUG)
                        mr              r3,r13                                  ; (TEST/DEBUG)
                        mr              r5,r14                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  

                        cmplw   cr1,r12,r17                             ; Are the "old" activation and the "new" the same?
                        cmplwi  cr2,r14,0                               ; Is there any saved context on the "old" activation?
                        bne+    cr1,fsmstsave                   ; The activations are different so "old" context must be saved...

;
;                       Here we know that both the "old" and "new" activations are the same.  We will
;                       check the current level and active levels.  If they are the same, the context is
;                       already live, so all we do is turn on the facility and invalidate the top
;                       savearea. 
;               
;                       If the current level, the active level, and the top savearea level are the
;                       same, then the context was saved as part of a thread context switch and neither
;                       needs saving or restoration.
;                       
;                       In all other cases, the context must be saved unless we are just re-enabling
;                       floating point.
;

                        cmplw   r13,r15                                 ; Are the levels the same?
                        cmplwi  cr2,r14,0                               ; Is there any saved context?
                        bne-    fsmstsave                               ; Levels are different, we need to save...
                        
                        beq-    cr2,fsenable                    ; No saved context at all, enable and go...
                        
                        lwz             r20,SAVlvlfp(r14)               ; Get the level of the top savearea

#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F03                               ; (TEST/DEBUG)
                        mr              r3,r15                                  ; (TEST/DEBUG)
                        mr              r5,r20                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        cmplw   r15,r20                                 ; Is the top level the same as the current?
                        li              r0,1                                    ; Get the invalid flag
                        bne-    fsenable                                ; Not the same, just enable and go...
                        
                        stw             r0,SAVlvlfp(r14)                ; Invalidate that top savearea

                        b               fsenable                                ; Then enable and go...
                        
;
;                       We need to save the "old" context here.  The LIFO queueing scheme works
;                       out for all cases because if both the "new" and "old" activations are the
;                       same, there can not be any saved state to load.  the "new" level is
;                       truely new.
;
;                       When we save the context, we either use a new savearea, or the free
;                       one that is cached at the head of the list.
                        
fsmstsave:      beq-    cr2,fsgetsave                   ; There is no possible cached save area
                        
                        lwz             r5,SAVlvlfp(r14)                ; Get the level of first facility savearea
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F04                               ; (TEST/DEBUG)
                        mr              r3,r15                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        mr              r3,r14                                  ; Assume we are invalid
                        cmplwi  r5,1                                    ; Is it invalid?
                        cmplw   cr1,r5,r13                              ; Is the SA level the active one?
                        beq+    fsusecache                              ; Invalid, just use it...
                        beq-    cr1,fsnosave                    ; The SA level is active, it is already saved...
                        
fsgetsave:      mr              r3,r4                                   ; Use the interrupt save as the context savearea if none cached
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F05                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        
                        bl              fpsrchsave                              ; Find a free savearea

                        stw             r3,ACT_MACT_FPU(r12)    ; Set this as the latest context savearea for the thread
                        mfsprg  r6,0                                    ; Get back per_processor block
                        stw             r14,SAVprefp(r3)                ; And then chain this in front
                        oris    r7,r7,hi16(SAVfpuvalid) ; Set the allocated bit
                        stw             r12,SAVact(r3)                  ; Make sure we point to the right guy
                        stw             r7,SAVflags(r3)                 ; Set the allocation flags

fsusecache:     la              r11,savefp0(r3)                 ; Point to the 1st line in area
                        stw             r13,SAVlvlfp(r3)                ; Set this context level
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F06                               ; (TEST/DEBUG)
                        mr              r5,r13                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  

;
;                       Now we will actually save the old context
;
                        
                        dcbz    0,r11                                   ; Allocate the output area

                        la              r11,savefp4(r3)                 ; Point to the 2nd line
                        stfd    f0,savefp0(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f1,savefp1(r3)
                        stfd    f2,savefp2(r3)
                        la              r11,savefp8(r3)                 ; Point to the 3rd line
                        stfd    f3,savefp3(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f4,savefp4(r3)
                        stfd    f5,savefp5(r3)
                        stfd    f6,savefp6(r3)
                        la              r11,savefp12(r3)                ; Point to the 4th line
                        stfd    f7,savefp7(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f8,savefp8(r3)
                        stfd    f9,savefp9(r3)
                        stfd    f10,savefp10(r3)
                        la              r11,savefp16(r3)                ; Point to the 5th line
                        stfd    f11,savefp11(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f12,savefp12(r3)
                        stfd    f13,savefp13(r3)
                        stfd    f14,savefp14(r3)
                        la              r11,savefp20(r3)                ; Point to the 6th line 
                        stfd    f15,savefp15(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f16,savefp16(r3)
                        stfd    f17,savefp17(r3)
                        stfd    f18,savefp18(r3)
                        la              r11,savefp24(r3)                ; Point to the 7th line
                        stfd    f19,savefp19(r3)
                        dcbz    0,r11                                   ; Allocate cache
                        stfd    f20,savefp20(r3)

                        li              r14,0                                   ; Clear this for now
                        lwz             r15,liveFPSCR(r6)               ; Get the previously saved FPSCR

                        stfd    f21,savefp21(r3)
                        stfd    f22,savefp22(r3)
                        la              r11,savefp28(r3)                ; Point to the 8th line
                        stfd    f23,savefp23(r3)
                        dcbz    0,r11                                   ; allocate it
                        stfd    f24,savefp24(r3)
                        stfd    f25,savefp25(r3)
                        stfd    f26,savefp26(r3)
                        la              r11,savefpscrpad(r3)    ; Point to the 9th line
                        stfd    f27,savefp27(r3)
                        dcbz    0,r11                                   ; allocate it
                        stfd    f28,savefp28(r3)
                        stfd    f29,savefp29(r3)
                        stfd    f30,savefp30(r3)
                        stfd    f31,savefp31(r3)

;                       Note that we just save the FPSCR here for ease.  It is really already saved
;                       in the "normal" context area of the savearea.

                        stw             r14,savefpscrpad(r3)    ; Save the FPSCR pad
                        stw             r15,savefpscr(r3)               ; Save the FPSCR

;
;                       The context is all saved now and the facility is free.
;
;                       Now check out the "new" and see if we need to load up his context.
;                       If we do (and this should be the normal case), do it and then invalidate the
;                       savearea. (This will keep it cached for quick access next time around.)
;                       
;                       If we do not (remember, we already took care of the case where we just enable
;                       the FPU), we need to fill the registers with junk, because this level has 
;                       never used them before and some thieving bastard could hack the old values
;                       of some thread!  Just imagine what would happen if they could!  Why, nothing
;                       would be safe! My God! It is terrifying!
;

                        
fsnosave:       lwz             r15,ACT_MACT_PCB(r17)   ; Get the current level of the "new" one
                        lwz             r14,ACT_MACT_FPU(r17)   ; Point to the top of the "new" context stack
                        lwz             r13,ACT_MACT_FPUlvl(r17)        ; Get the "new" active level
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F07                               ; (TEST/DEBUG)
                        mr              r1,r15                                  ; (TEST/DEBUG)
                        mr              r3,r14                                  ; (TEST/DEBUG)
                        mr              r5,r13                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  

                        cmplwi  cr1,r14,0                               ; Do we possibly have some context to load?
                        stw             r15,ACT_MACT_FPUlvl(r17)        ; Set the "new" active level
                        stw             r18,ACT_MACT_FPUcpu(r17)        ; Set the active CPU
                        la              r11,savefp0(r14)                ; Point to first line to bring in
                        stw             r17,PP_FPU_THREAD(r6)   ; Store current thread address in fpu_thread to claim fpu for thread
                        
                        beq+    cr1,MakeSureThatNoTerroristsCanHurtUsByGod      ; No "new" context to load...
                        lwz             r0,SAVlvlfp(r14)                ; Get the level of first facility savearea
                        cmplw   r0,r15                                  ; Top level correct to load?
                        bne-    MakeSureThatNoTerroristsCanHurtUsByGod  ; No, go initialize...
                        
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F08                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  

                        dcbt    0,r11                                   ; Touch line in
                        li              r0,1                                    ; Get the level invalid indication
                                                
                        la              r11,savefp4(r14)                ; Point to next line
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f0, savefp0(r14)
                        lfd     f1,savefp1(r14)
                        stw             r0,SAVlvlfp(r14)                ; Mark the savearea invalid because we are activating again
                        lfd     f2,savefp2(r14)
                        la              r11,savefp8(r14)                ; Point to next line
                        lfd     f3,savefp3(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f4,savefp4(r14)
                        lfd     f5,savefp5(r14)
                        lfd     f6,savefp6(r14)
                        la              r11,savefp12(r14)               ; Point to next line
                        lfd     f7,savefp7(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f8,savefp8(r14)
                        lfd     f9,savefp9(r14)
                        lfd     f10,savefp10(r14)
                        la              r11,savefp16(r14)               ; Point to next line
                        lfd     f11,savefp11(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f12,savefp12(r14)
                        lfd     f13,savefp13(r14)
                        lfd     f14,savefp14(r14)
                        la              r11,savefp20(r14)               ; Point to next line
                        lfd     f15,savefp15(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f16,savefp16(r14)
                        lfd     f17,savefp17(r14)
                        lfd     f18,savefp18(r14)
                        la              r11,savefp24(r14)               ; Point to next line
                        lfd     f19,savefp19(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f20,savefp20(r14)
                        lfd     f21,savefp21(r14)
                        la              r11,savefp28(r14)               ; Point to next line
                        lfd     f22,savefp22(r14)
                        lfd     f23,savefp23(r14)
                        dcbt    0,r11                                   ; Touch line in
                        lfd     f24,savefp24(r14)
                        lfd     f25,savefp25(r14)
                        lfd     f26,savefp26(r14)
                        lfd     f27,savefp27(r14)
                        lfd     f28,savefp28(r14)
                        lfd     f29,savefp29(r14)
                        lfd     f30,savefp30(r14)
                        lfd     f31,savefp31(r14)
                        
fsenable:       lwz             r9,SAVflags(r4)                 /* Get the flags of the current savearea */
                        lwz             r8,savesrr1(r4)                 ; Get the msr of the interrupted guy
                        rlwinm  r5,r4,0,0,19                    /* Get the page address of the savearea */
                        ori             r8,r8,MASK(MSR_FP)              ; Enable the floating point feature
                        lwz             r10,ACT_MACT_SPF(r17)   ; Get the special flags
                        lis             r7,hi16(SAVattach)              /* Get the attached flag */
                        lwz             r5,SACvrswap(r5)                /* Get Virtual to Real translation */
                        oris    r10,r10,hi16(floatUsed|floatCng)        ; Set that we used floating point
                        mr.             r15,r15                                 ; See if we are doing this for user state
                        stw             r8,savesrr1(r4)                 ; Set the msr of the interrupted guy
                        andc    r9,r9,r7                                /* Clear the attached bit */
                        xor             r3,r4,r5                                /* Get the real address of the savearea */
                        bne-    fsnuser                                 ; We are not user state...
                        stw             r10,ACT_MACT_SPF(r17)   ; Set the activation copy
                        stw             r10,spcFlags(r6)                ; Set per_proc copy

fsnuser:
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F0A                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        stw             r9,SAVflags(r4)                 /* Set the flags of the current savearea */
                        
                        b               EXT(exception_exit)             /* Exit from the fray... */

/*
 *                      Initialize the registers to some bogus value
 */

MakeSureThatNoTerroristsCanHurtUsByGod:
                        
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x7F09                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  
                        lis             r5,hi16(EXT(FloatInit)) /* Get top secret floating point init value address */
                        ori             r5,r5,lo16(EXT(FloatInit))      /* Slam bottom */
                        lfd             f0,0(r5)                                /* Initialize FP0 */
                        fmr             f1,f0                                   ; Do them all                                           
                        fmr             f2,f0                                                           
                        fmr             f3,f0                                                           
                        fmr             f4,f0                                                           
                        fmr             f5,f0                                           
                        fmr             f6,f0                                           
                        fmr             f7,f0                                           
                        fmr             f8,f0                                           
                        fmr             f9,f0                                           
                        fmr             f10,f0                                          
                        fmr             f11,f0                                          
                        fmr             f12,f0                                          
                        fmr             f13,f0                                          
                        fmr             f14,f0                                          
                        fmr             f15,f0                                          
                        fmr             f16,f0                                          
                        fmr             f17,f0
                        fsub    f31,f31,f31                             ; Get set to initialize the FPSCR
                        fmr             f18,f0                                          
                        fmr             f19,f0                                          
                        fmr             f20,f0                                          
                        mtfsf   0xff,f31                                ; Clear all FPSCR exception eanbles
                        fmr             f21,f0                                          
                        fmr             f22,f0                                          
                        fmr             f23,f0                                          
                        fmr             f24,f0                                          
                        fmr             f25,f0                                          
                        fmr             f26,f0                                          
                        fmr             f27,f0                                          
                        fmr             f28,f0                                          
                        fmr             f29,f0                                          
                        fmr             f30,f0                                          
                        fmr             f31,f0                                          
                        b               fsenable                                ; Finish setting it all up...                           

;
;                       Finds an unused floating point area in the activation pointed
;                       to by R12s saved contexts.  If none are found (unlikely but possible)
;                       and R3 is 0, a new area is allocated.  If R3 is non-zero, it contains 
;                       a pointer to an floating point savearea that is free.
;
fpsrchsave:
                        lwz             r6,ACT_MACT_PCB(r12)            ; Get the first "normal" savearea
                        
fpsrnorm:       mr.             r5,r6                                           ; Is there another?
                        beq-    fpsrvect                                        ; No, search the vector saveareas...
                        lwz             r7,SAVflags(r5)                         ; Get the flags for this guy
                        lwz             r6,SAVprev(r5)                          ; Get the previous savearea, just in case
                        andis.  r8,r7,hi16(SAVfpuvalid)         ; Have we found an empty FPU save in normal?
                        beq+    fpsrgot                                         ; We found one...
                        b               fpsrnorm                                        ; Search again...

fpsrvect:       lwz             r6,ACT_MACT_VMX(r12)            ; Get the first "vector" savearea
                        
fpsrvectx:      mr.             r5,r6                                           ; Is there another?
                        beq-    fpsrget                                         ; No, try to allocate one...
                        lwz             r7,SAVflags(r5)                         ; Get the flags for this guy
                        lwz             r6,SAVprevec(r5)                        ; Get the previous savearea, just in case
                        andis.  r8,r7,hi16(SAVfpuvalid)         ; Have we found an empty FPU save in vector?
                        bne-    fpsrvectx                                       ; Search again...
                        
fpsrgot:        mr              r3,r5                                           ; Get the savearea into the right register
                        blr                                                                     ; Return...

fpsrget:        mr.             r5,r3                                           ; Do we allocate or use existing?
                        beq+    fpsrallo                                        ; Allocate one...
                        
                        lwz             r7,SAVflags(r3)                         ; Get the passed in area flags
                        blr                                                                     ; Return...
;                       
;                       NOTE: save_get will return directly and set R7 to 0...
;
fpsrallo:       b               EXT(save_get)                           ; Get a fresh savearea 

/*
 *                      Altivec stuff is here. The techniques used are pretty identical to
 *                      the floating point. Except that we will honor the VRSAVE register
 *                      settings when loading and restoring registers.
 *
 *                      There are two indications of saved VRs: the VRSAVE register and the vrvalid
 *                      mask. VRSAVE is set by the vector user and represents the VRs that they
 *                      say that they are using. The vrvalid mask indicates which vector registers
 *                      are saved in the savearea. Whenever context is saved, it is saved according
 *                      to the VRSAVE register.  It is loaded based on VRSAVE anded with
 *                      vrvalid (all other registers are splatted with 0s). This is done because we
 *                      don't want to load any registers we don't have a copy of, we want to set them
 *                      to zero instead.
 *
 */

ENTRY(vec_save, TAG_NO_FRAME_USED)

                        mfmsr   r0                                              ; Get the MSR
                        rlwinm  r0,r0,0,MSR_VEC_BIT+1,MSR_VEC_BIT-1     ; Turn off vector forever
                        rlwinm  r2,r0,0,MSR_EE_BIT+1,MSR_EE_BIT-1       ; But do interrupts only for now
                        oris    r2,r2,hi16(MASK(MSR_VEC))       ; Enable the vector facility for now also
                        mtmsr   r2                                              ; Set the MSR
                        isync
                
                        mfsprg  r6,0                                    ; Get the per_processor block 
                        lwz             r12,PP_VMX_THREAD(r6)   ; Get the thread that owns the vector
#if FPVECDBG
                        mr              r7,r0                                   ; (TEST/DEBUG)
                        li              r4,0                                    ; (TEST/DEBUG)
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        mr.             r3,r12                                  ; (TEST/DEBUG)
                        li              r2,0x5F00                               ; (TEST/DEBUG)
                        li              r5,0                                    ; (TEST/DEBUG)
                        beq-    noowneryeu                              ; (TEST/DEBUG)
                        lwz             r4,ACT_MACT_VMXlvl(r12) ; (TEST/DEBUG)
                        lwz             r5,ACT_MACT_VMX(r12)    ; (TEST/DEBUG)

noowneryeu:     oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
                        mr              r0,r7                                   ; (TEST/DEBUG)
#endif  
                        mflr    r2                                              ; Save the return address
                        lwz             r10,PP_CPU_DATA(r6)             ; Get the CPU data pointer
                        lhz             r11,PP_CPU_NUMBER(r6)   ; Get our CPU number
                        
                        mr.             r12,r12                                 ; Anyone own the vector?
                        
                        lwz             r10,CPU_ACTIVE_THREAD(r10)      ; Get the pointer to the active thread
                        
                        beq-    vsret                                   ; Nobody owns the vector, no save required...
                        
                        lwz             r10,THREAD_TOP_ACT(r10) ; Now get the activation that is running
                        lwz             r9,ACT_MACT_VMXcpu(r12) ; Get the last CPU to use this context
                        
                        cmplw   r12,r10                                 ; Do we own the thread?
                        cmplw   cr1,r9,r11                              ; Was the context for this processor? 
                        bne+    vsret                                   ; Facility belongs to some other activation...
                        li              r3,0                                    ; Assume we need a fix-me-up
                        beq-    cr1,vsgoodcpu                   ; Facility last used on this processor...
                        stw             r3,PP_VMX_THREAD(r6)    ; Clear owner because it was really on the other processor
                        b               vsret                                   ; Bail now with no save...
                        
vsgoodcpu:      lwz             r3,ACT_MACT_VMX(r12)    ; Get the current vector savearea for the thread
                        lwz             r9,ACT_MACT_VMXlvl(r12) ; Get our current level indicator
                        
                        cmplwi  cr1,r3,0                                ; Have we ever saved this facility context?
                        beq-    cr1,vsneedone                   ; Never saved it, so we need an area...
                        
                        lwz             r8,SAVlvlvec(r3)                ; Get the level this savearea is for
                        cmplwi  r8,1                                    ; See if this is a spare
                        cmplw   cr1,r9,r8                               ; Correct level?
                        beq+    vsusespare                              ; It is still live...
                        beq-    cr1,vsret                               ; The current level is already saved, bail out...

vsneedone:      li              r3,0                                    ; Tell the routine to allocate an area if none found
                        bl              vsrchsave                               ; Find a free savearea
                        
                        mfsprg  r6,0                                    ; Get back per_processor block
                        oris    r7,r7,hi16(SAVvmxvalid) ; Set the allocated bit
                        lwz             r12,PP_VMX_THREAD(r6)   ; Get back our thread
                        mtlr    r2                                              ; Restore return
                        lwz             r8,ACT_MACT_VMX(r12)    ; Get the current top vector savearea
                        lwz             r9,ACT_MACT_VMXlvl(r12) ; Get our current level indicator again         
                        stw             r3,ACT_MACT_VMX(r12)    ; Set this as the latest vector savearea for the thread
                        stw             r8,SAVprevec(r3)                ; And then chain this in front
                        stw             r7,SAVflags(r3)                 ; Set the allocation flags
                        stw             r12,SAVact(r3)                  ; Make sure we point to the right guy

vsusespare:     stw             r9,SAVlvlvec(r3)                ; And set the level this savearea is for
                        mfcr    r2                                              ; Save non-volatile CRs
                        lwz             r10,liveVRS(r6)                 ; Get the right VRSave register
                        lis             r9,0x5555                               ; Mask with odd bits set                
                        rlwinm  r11,r10,1,0,31                  ; Shift over 1
                        ori             r9,r9,0x5555                    ; Finish mask
                        or              r12,r10,r11                             ; After this, even bits show which lines to zap
                        
                        andc    r11,r12,r9                              ; Clear out odd bits
                        
                        la              r6,savevr0(r3)                  ; Point to line 0
                        rlwinm  r4,r11,15,0,15                  ; Move line 8-15 flags to high order odd bits
                        la              r9,savevrvalid(r3)              ; Point to the saved register mask field
                        or              r4,r11,r4                               ; Set the odd bits
                                                                                        ; (bit 0 is line 0, bit 1 is line 8,
                                                                                        ; bit 2 is line 1, bit 3 is line 9, etc.
                        dcba    br0,r9                                  ; Allocate the cache for it
                        rlwimi  r4,r10,16,16,31                 ; Put vrsave 0 - 15 into positions 16 - 31
                        la              r7,savevr2(r3)                  ; Point to line 1
                        mtcrf   255,r4                                  ; Load up the CRs
                        stw             r10,savevrvalid(r3)             ; Save the validity information
                        mr              r8,r6                                   ; Start registers off
;       
;                       Save the current vector state
;
                                                
                        bf              0,snol0                                 ; No line 0 to do...
                        dcba    br0,r6                                  ; Allocate cache line 0
                        
snol0:          
                        la              r6,savevr4(r3)                  ; Point to line 2
                        bf              2,snol1                                 ; No line 1 to do...
                        dcba    br0,r7                                  ; Allocate cache line 1
                        
snol1:          
                        la              r7,savevr6(r3)                  ; Point to line 3
                        bf              4,snol2                                 ; No line 2 to do...
                        dcba    br0,r6                                  ; Allocate cache line 2
                        
snol2:          
                        li              r11,16                                  ; Get offset for odd registers
                        bf              16,snovr0                               ; Do not save VR0...
                        stvxl   v0,br0,r8                               ; Save VR0
                        
snovr0:         
                        la              r9,savevr2(r3)                  ; Point to V2/V3 pair
                        bf              17,snovr1                               ; Do not save VR1...
                        stvxl   v1,r11,r8                               ; Save VR1
                        
snovr1:
                        la              r6,savevr8(r3)                  ; Point to line 4
                        bf              6,snol3                                 ; No line 3 to do...
                        dcba    br0,r7                                  ; Allocate cache line 3
                        
snol3:          
                        la              r8,savevr4(r3)                  ; Point to V4/V5 pair
                        bf              18,snovr2                               ; Do not save VR2...
                        stvxl   v2,br0,r9                               ; Save VR2
                        
snovr2:
                        bf              19,snovr3                               ; Do not save VR3...
                        stvxl   v3,r11,r9                               ; Save VR3
                        
snovr3:
;
;                       Note: CR4 is now free
;
                        la              r7,savevr10(r3)                 ; Point to line 5
                        bf              8,snol4                                 ; No line 4 to do...
                        dcba    br0,r6                                  ; Allocate cache line 4
                        
snol4:          
                        la              r9,savevr6(r3)                  ; Point to R6/R7 pair
                        bf              20,snovr4                               ; Do not save VR4...
                        stvxl   v4,br0,r8                               ; Save VR4
                        
snovr4:
                        bf              21,snovr5                               ; Do not save VR5...
                        stvxl   v5,r11,r8                               ; Save VR5
                        
snovr5:
                        mtcrf   0x08,r10                                ; Set CRs for registers 16-19
                        la              r6,savevr12(r3)                 ; Point to line 6
                        bf              10,snol5                                ; No line 5 to do...
                        dcba    br0,r7                                  ; Allocate cache line 5
                        
snol5:          
                        la              r8,savevr8(r3)                  ; Point to V8/V9 pair
                        bf              22,snovr6                               ; Do not save VR6...
                        stvxl   v6,br0,r9                               ; Save VR6
                        
snovr6:
                        bf              23,snovr7                               ; Do not save VR7...
                        stvxl   v7,r11,r9                               ; Save VR7
                        
snovr7:
;
;                       Note: CR5 is now free
;
                        la              r7,savevr14(r3)                 ; Point to line 7
                        bf              12,snol6                                ; No line 6 to do...
                        dcba    br0,r6                                  ; Allocate cache line 6
                        
snol6:          
                        la              r9,savevr10(r3)                 ; Point to V10/V11 pair
                        bf              24,snovr8                               ; Do not save VR8...
                        stvxl   v8,br0,r8                               ; Save VR8
                        
snovr8:
                        bf              25,snovr9                               ; Do not save VR9...
                        stvxl   v9,r11,r8                               ; Save VR9
                        
snovr9:
                        mtcrf   0x04,r10                                ; Set CRs for registers 20-23
                        la              r6,savevr16(r3)                 ; Point to line 8
                        bf              14,snol7                                ; No line 7 to do...
                        dcba    br0,r7                                  ; Allocate cache line 7
                        
snol7:          
                        la              r8,savevr12(r3)                 ; Point to V12/V13 pair
                        bf              26,snovr10                              ; Do not save VR10...
                        stvxl   v10,br0,r9                              ; Save VR10
                        
snovr10:
                        bf              27,snovr11                              ; Do not save VR11...
                        stvxl   v11,r11,r9                              ; Save VR11
                        
snovr11:

;
;                       Note: CR6 is now free
;
                        la              r7,savevr18(r3)                 ; Point to line 9
                        bf              1,snol8                                 ; No line 8 to do...
                        dcba    br0,r6                                  ; Allocate cache line 8
                        
snol8:          
                        la              r9,savevr14(r3)                 ; Point to V14/V15 pair
                        bf              28,snovr12                              ; Do not save VR12...
                        stvxl   v12,br0,r8                              ; Save VR12
                        
snovr12:
                        bf              29,snovr13                              ; Do not save VR13...
                        stvxl   v13,r11,r8                              ; Save VR13
                        
snovr13:
                        mtcrf   0x02,r10                                ; Set CRs for registers 24-27
                        la              r6,savevr20(r3)                 ; Point to line 10
                        bf              3,snol9                                 ; No line 9 to do...
                        dcba    br0,r7                                  ; Allocate cache line 9
                        
snol9:          
                        la              r8,savevr16(r3)                 ; Point to V16/V17 pair
                        bf              30,snovr14                              ; Do not save VR14...
                        stvxl   v14,br0,r9                              ; Save VR14
                        
snovr14:
                        bf              31,snovr15                              ; Do not save VR15...
                        stvxl   v15,r11,r9                              ; Save VR15
                        
snovr15:
;
;                       Note: CR7 is now free
;
                        la              r7,savevr22(r3)                 ; Point to line 11
                        bf              5,snol10                                ; No line 10 to do...
                        dcba    br0,r6                                  ; Allocate cache line 10
                        
snol10:         
                        la              r9,savevr18(r3)                 ; Point to V18/V19 pair
                        bf              16,snovr16                              ; Do not save VR16...
                        stvxl   v16,br0,r8                              ; Save VR16
                        
snovr16:
                        bf              17,snovr17                              ; Do not save VR17...
                        stvxl   v17,r11,r8                              ; Save VR17
                        
snovr17:
                        mtcrf   0x01,r10                                ; Set CRs for registers 28-31
;
;                       Note: All registers have been or are accounted for in CRs
;
                        la              r6,savevr24(r3)                 ; Point to line 12
                        bf              7,snol11                                ; No line 11 to do...
                        dcba    br0,r7                                  ; Allocate cache line 11
                        
snol11:         
                        la              r8,savevr20(r3)                 ; Point to V20/V21 pair
                        bf              18,snovr18                              ; Do not save VR18...
                        stvxl   v18,br0,r9                              ; Save VR18
                        
snovr18:
                        bf              19,snovr19                              ; Do not save VR19...
                        stvxl   v19,r11,r9                              ; Save VR19
                        
snovr19:
                        la              r7,savevr26(r3)                 ; Point to line 13
                        bf              9,snol12                                ; No line 12 to do...
                        dcba    br0,r6                                  ; Allocate cache line 12
                        
snol12:         
                        la              r9,savevr22(r3)                 ; Point to V22/V23 pair
                        bf              20,snovr20                              ; Do not save VR20...
                        stvxl   v20,br0,r8                              ; Save VR20
                        
snovr20:
                        bf              21,snovr21                              ; Do not save VR21...
                        stvxl   v21,r11,r8                              ; Save VR21
                        
snovr21:
                        la              r6,savevr28(r3)                 ; Point to line 14
                        bf              11,snol13                               ; No line 13 to do...
                        dcba    br0,r7                                  ; Allocate cache line 13
                        
snol13:         
                        la              r8,savevr24(r3)                 ; Point to V24/V25 pair
                        bf              22,snovr22                              ; Do not save VR22...
                        stvxl   v22,br0,r9                              ; Save VR22
                        
snovr22:
                        bf              23,snovr23                              ; Do not save VR23...
                        stvxl   v23,r11,r9                              ; Save VR23
                        
snovr23:
                        la              r7,savevr30(r3)                 ; Point to line 15
                        bf              13,snol14                               ; No line 14 to do...
                        dcba    br0,r6                                  ; Allocate cache line 14
                        
snol14:         
                        la              r9,savevr26(r3)                 ; Point to V26/V27 pair
                        bf              24,snovr24                              ; Do not save VR24...
                        stvxl   v24,br0,r8                              ; Save VR24
                        
snovr24:
                        bf              25,snovr25                              ; Do not save VR25...
                        stvxl   v25,r11,r8                              ; Save VR25
                        
snovr25:
                        bf              15,snol15                               ; No line 15 to do...
                        dcba    br0,r7                                  ; Allocate cache line 15
                        
snol15:         
;
;                       Note: All cache lines allocated now
;
                        la              r8,savevr28(r3)                 ; Point to V28/V29 pair
                        bf              26,snovr26                              ; Do not save VR26...
                        stvxl   v26,br0,r9                              ; Save VR26

snovr26:
                        bf              27,snovr27                              ; Do not save VR27...
                        stvxl   v27,r11,r9                              ; Save VR27
                        
snovr27:
                        la              r7,savevr30(r3)                 ; Point to V30/V31 pair
                        bf              28,snovr28                              ; Do not save VR28...
                        stvxl   v28,br0,r8                              ; Save VR28
                        
snovr28:                
                        bf              29,snovr29                              ; Do not save VR29...
                        stvxl   v29,r11,r8                              ; Save VR29
                        
snovr29:                
                        mfvscr  v27                                             ; Get the VSCR
                        la              r8,savevscr(r3)                 ; Point to the VSCR save area
                        bf              30,snovr30                              ; Do not save VR30...
                        stvxl   v30,br0,r7                              ; Save VR30
                        
snovr30:
                        dcba    br0,r8                                  ; Allocate VSCR savearea
                        bf              31,snovr31                              ; Do not save VR31...
                        stvxl   v31,r11,r7                              ; Save VR31
                        
snovr31:
                        add             r11,r11,r9                              ; Point to V27s saved value
                        stvxl   v27,br0,r8                              ; Save the VSCR
                        bt              27,v27ok                                ; V27 has been saved and is marked as wanted
                
                        lis             r11,hi16(EXT(QNaNbarbarian))    ; V27 is not wanted, so get empty value
                        ori             r11,r11,lo16(EXT(QNaNbarbarian))

v27ok:          mtcrf   255,r2                                  ; Restore all non-volatile CRs
                        lvxl    v27,br0,r11                             ; Restore or load empty value into V27 because we used it       

;
;                       Save the current vector state into the savearea of the thread that owns it.
; 

vsret:          mtmsr   r0                                              ; Put interrupts on if they were and vector off
                        isync

                        blr

/*
 * vec_switch()
 *
 * Entered to handle the vector unavailable exception and
 * switch vector context
 *
 * This code is run with virtual address mode on and interrupts off.
 *
 * Upon exit, the code returns to the users context with the vector
 * facility turned on.
 *
 * ENTRY:       VM switched ON
 *              Interrupts  OFF
 *              State is saved in savearea pointed to by R4.
 *                              All other registers are free.
 * 
 */

ENTRY(vec_switch, TAG_NO_FRAME_USED)

#if DEBUG
#if GDDBG
                        mr              r7,r4                                   ; Save input parameter
                        lis             r3,hi16(EXT(vec_trap_count))    ; Get address of vector trap counter
                        ori             r3,r3,lo16(EXT(vec_trap_count)) ; Get address of vector trap counter
                        lwz             r1,0(r3)
                        lis             r5,hi16(EXT(GratefulDeb))       ; Point to top of display
                        ori             r5,r5,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        addi    r1,r1,1
                        mtlr    r5                                              ; Set link register
                        stw             r1,0(r3)
                        mr              r4,r1
                        lis             r3,1
                        blrl                                                    ; Display count
                        mr              r4,r7                                   ; Restore the parameter
#else
                        lis             r3,hi16(EXT(vec_trap_count))    ; Get address of vector trap counter
                        ori             r3,r3,lo16(EXT(vec_trap_count)) ; Get address of vector trap counter
                        lwz             r1,0(r3)
                        addi    r1,r1,1
                        stw             r1,0(r3)
#endif
#endif /* DEBUG */

                        mfsprg  r6,0                                    /* Get the per_processor block */
                        mfmsr   r19                                             /* Get the current MSR */
                        
                        lwz             r10,PP_CPU_DATA(r6)             /* Get the CPU data pointer */
                        lwz             r12,PP_VMX_THREAD(r6)   /* Get the thread that owns the vector */
                        lwz             r10,CPU_ACTIVE_THREAD(r10)      /* Get the pointer to the active thread */
                        oris    r19,r19,hi16(MASK(MSR_VEC))     /* Enable the vector feature */
                        lwz             r17,THREAD_TOP_ACT(r10) /* Now get the activation that is running */
                        
;                       R12 has the "old" activation
;                       R17 has the "new" activation

#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F01                               ; (TEST/DEBUG)
                        mr              r3,r12                                  ; (TEST/DEBUG)
                        mr              r5,r17                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r18,r4                                  ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r18                                  ; Restore it
                        mfsprg  r6,0                                    ; Get the per_processor block back
#endif
#endif  
                        mr.             r12,r12                                 ; See if there is any live vector status
                        
                        lhz             r18,PP_CPU_NUMBER(r6)   ; Get our CPU number
                
                        mtmsr   r19                                             /* Set vector available */
                        isync
                        
                        
                        beq-    vsnosave                                ; No live context, so nothing to save...
        
                        lwz             r19,ACT_MACT_VMXcpu(r12)        ; Get the "old" active CPU
                        lwz             r15,ACT_MACT_PCB(r12)   ; Get the current level of the "old" one
                        cmplw   r18,r19                                 ; Check the CPU that the old context is live on
                        lwz             r14,ACT_MACT_VMX(r12)   ; Point to the top of the old context stack
                        bne-    vsnosave                                ; Context is not live if used on a different CPU...
                        lwz             r13,ACT_MACT_VMXlvl(r12)        ; Get the "old" active level
                        
;
;                       First, check to see if all we are doing is enabling because the
;                       "new" context is live.
;
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F02                               ; (TEST/DEBUG)
                        mr              r1,r15                                  ; (TEST/DEBUG)
                        mr              r3,r13                                  ; (TEST/DEBUG)
                        mr              r5,r14                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
#endif
#endif  

                        cmplw   cr1,r12,r17                             ; Is the "old" activation and the "new" the same?
                        cmplwi  cr2,r14,0                               ; Is there any saved context on the "old" activation?
                        bne+    cr1,vsmstsave                   ; The activations are different so "old" context must be saved...

;
;                       Here we know that both the "old" and "new" activations are the same.  We will
;                       check the current level and active levels.  If they are the same, the context is
;                       already live, so all we do is turn on the facility and invalidate the top
;                       savearea. 
;               
;                       If the current level, the active level, and the top savearea level are the
;                       same, then the context was saved as part of a thread context switch and neither
;                       needs saving or restoration.
;                       
;                       In all other cases, the context must be saved unless we are just re-enabling
;                       vector.
;

                        cmplw   r13,r15                                 ; Are the levels the same?
                        cmplwi  cr2,r14,0                               ; Is there any saved context?
                        bne-    vsmstsave                               ; Levels are different, we need to save...
                        
                        beq-    cr2,vrenable                    ; No saved context at all, enable and go...
                        
                        lwz             r20,SAVlvlvec(r14)              ; Get the level of the top savearea

#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F03                               ; (TEST/DEBUG)
                        mr              r3,r15                                  ; (TEST/DEBUG)
                        mr              r5,r20                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
#endif
#endif  
                        cmplw   r15,r20                                 ; Is the top level the same as the current?
                        li              r0,1                                    ; Get the invalid flag
                        bne-    vrenable                                ; Not the same, just enable and go...
                        
                        stw             r0,SAVlvlvec(r14)               ; Invalidate that top savearea

                        b               vrenable                                ; Then enable and go...
                        
;
;                       We need to save the "old" context here.  The LIFO queueing scheme works
;                       out for all cases because if both the "new" and "old" activations are the
;                       same, there can not be any saved state to load.  the "new" level is
;                       truely new.
;
;                       When we save the context, we either use a new savearea, or the free
;                       one that is cached at the head of the list.
                        
vsmstsave:      beq-    cr2,vsgetsave                   ; There is no possible cached save area
                        
                        lwz             r5,SAVlvlvec(r14)               ; Get the level of first facility savearea
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F04                               ; (TEST/DEBUG)
                        mr              r3,r15                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        mr              r7,r5                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
                        mr              r5,r7                                   ; Restore it
#endif
#endif  
                        mr              r3,r14                                  ; Assume we are invalid
                        cmplwi  r5,1                                    ; Is it invalid?
                        cmplw   cr1,r5,r13                              ; Is the SA level the active one?
                        beq+    vsusecache                              ; Invalid, just use it...
                        beq-    cr1,vsnosave                    ; The SA level is active, it is already saved...
                        
vsgetsave:      mr              r3,r4                                   ; Use the interrupt save as the context savearea if none cached
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F05                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
                        mr              r3,r8                                   ; This too
#endif
#endif  
                        
                        bl              vsrchsave                               ; Find a free savearea

                        stw             r3,ACT_MACT_VMX(r12)    ; Set this as the latest context savearea for the thread
                        mfsprg  r6,0                                    ; Get back per_processor block
                        stw             r14,SAVprevec(r3)               ; And then chain this in front
                        oris    r7,r7,hi16(SAVvmxvalid) ; Set the allocated bit
                        stw             r12,SAVact(r3)                  ; Make sure we point to the right guy
                        stw             r7,SAVflags(r3)                 ; Set the allocation flags

vsusecache:     la              r11,savevr0(r3)                 ; Point to the 1st line in area
                        stw             r13,SAVlvlvec(r3)               ; Set this context level
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F06                               ; (TEST/DEBUG)
                        mr              r5,r13                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        mr              r10,r3
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
                        mr              r3,r10
                        mfsprg  r6,0                                    ; Get back per_processor block
#endif
#endif  

vsgotsave:      
                        lwz             r10,liveVRS(r6)                 ; Get the right VRSave register
                        lis             r9,0x5555                               ; Mask with odd bits set                
                        rlwinm  r11,r10,1,0,31                  ; Shift over 1
                        ori             r9,r9,0x5555                    ; Finish mask
                        or              r12,r10,r11                             ; After this, even bits show which lines to zap
                        
                        stw             r13,SAVlvlvec(r3)               ; Set the savearea level
                        andc    r13,r12,r9                              ; Clear out odd bits
                        
                        la              r20,savevr0(r3)                 ; Point to line 0
                        rlwinm  r24,r13,15,0,15                 ; Move line 8-15 flags to high order odd bits
                        la              r23,savevrvalid(r3)             ; Point to the saved register mask field
                        or              r24,r13,r24                             ; Set the odd bits
                                                                                        ; (bit 0 is line 0, bit 1 is line 8,
                                                                                        ; bit 2 is line 1, bit 3 is line 9, etc.
                        dcba    br0,r23                                 ; Allocate the cache for it
                        rlwimi  r24,r10,16,16,31                ; Put vrsave 0 - 15 into positions 16 - 31
                        la              r21,savevr2(r3)                 ; Point to line 1
                        mtcrf   255,r24                                 ; Load up the CRs
                        stw             r10,savevrvalid(r3)             ; Save the validity information
                        mr              r22,r20                                 ; Start registers off
;       
;                       Save the current vector state
;
                                                
                        bf              0,nol0                                  ; No line 0 to do...
                        dcba    br0,r20                                 ; Allocate cache line 0
                        
nol0:           
                        la              r20,savevr4(r3)                 ; Point to line 2
                        bf              2,nol1                                  ; No line 1 to do...
                        dcba    br0,r21                                 ; Allocate cache line 1
                        
nol1:           
                        la              r21,savevr6(r3)                 ; Point to line 3
                        bf              4,nol2                                  ; No line 2 to do...
                        dcba    br0,r20                                 ; Allocate cache line 2
                        
nol2:           
                        li              r30,16                                  ; Get offset for odd registers
                        bf              16,novr0                                ; Do not save VR0...
                        stvxl   v0,br0,r22                              ; Save VR0
                        
novr0:          
                        la              r23,savevr2(r3)                 ; Point to V2/V3 pair
                        bf              17,novr1                                ; Do not save VR1...
                        stvxl   v1,r30,r22                              ; Save VR1
                        
novr1:
                        la              r20,savevr8(r3)                 ; Point to line 4
                        bf              6,nol3                                  ; No line 3 to do...
                        dcba    br0,r21                                 ; Allocate cache line 3
                        
nol3:           
                        la              r22,savevr4(r3)                 ; Point to V4/V5 pair
                        bf              18,novr2                                ; Do not save VR2...
                        stvxl   v2,br0,r23                              ; Save VR2
                        
novr2:
                        bf              19,novr3                                ; Do not save VR3...
                        stvxl   v3,r30,r23                              ; Save VR3
                        
novr3:
;
;                       Note: CR4 is now free
;
                        la              r21,savevr10(r3)                ; Point to line 5
                        bf              8,nol4                                  ; No line 4 to do...
                        dcba    br0,r20                                 ; Allocate cache line 4
                        
nol4:           
                        la              r23,savevr6(r3)                 ; Point to R6/R7 pair
                        bf              20,novr4                                ; Do not save VR4...
                        stvxl   v4,br0,r22                              ; Save VR4
                        
novr4:
                        bf              21,novr5                                ; Do not save VR5...
                        stvxl   v5,r30,r22                              ; Save VR5
                        
novr5:
                        mtcrf   0x08,r10                                ; Set CRs for registers 16-19
                        la              r20,savevr12(r3)                ; Point to line 6
                        bf              10,nol5                                 ; No line 5 to do...
                        dcba    br0,r21                                 ; Allocate cache line 5
                        
nol5:           
                        la              r22,savevr8(r3)                 ; Point to V8/V9 pair
                        bf              22,novr6                                ; Do not save VR6...
                        stvxl   v6,br0,r23                              ; Save VR6
                        
novr6:
                        bf              23,novr7                                ; Do not save VR7...
                        stvxl   v7,r30,r23                              ; Save VR7
                        
novr7:
;
;                       Note: CR5 is now free
;
                        la              r21,savevr14(r3)                ; Point to line 7
                        bf              12,nol6                                 ; No line 6 to do...
                        dcba    br0,r20                                 ; Allocate cache line 6
                        
nol6:           
                        la              r23,savevr10(r3)                ; Point to V10/V11 pair
                        bf              24,novr8                                ; Do not save VR8...
                        stvxl   v8,br0,r22                              ; Save VR8
                        
novr8:
                        bf              25,novr9                                ; Do not save VR9...
                        stvxl   v9,r30,r22                              ; Save VR9
                        
novr9:
                        mtcrf   0x04,r10                                ; Set CRs for registers 20-23
                        la              r20,savevr16(r3)                ; Point to line 8
                        bf              14,nol7                                 ; No line 7 to do...
                        dcba    br0,r21                                 ; Allocate cache line 7
                        
nol7:           
                        la              r22,savevr12(r3)                ; Point to V12/V13 pair
                        bf              26,novr10                               ; Do not save VR10...
                        stvxl   v10,br0,r23                             ; Save VR10
                        
novr10:
                        bf              27,novr11                               ; Do not save VR11...
                        stvxl   v11,r30,r23                             ; Save VR11
                        
novr11:

;
;                       Note: CR6 is now free
;
                        la              r21,savevr18(r3)                ; Point to line 9
                        bf              1,nol8                                  ; No line 8 to do...
                        dcba    br0,r20                                 ; Allocate cache line 8
                        
nol8:           
                        la              r23,savevr14(r3)                ; Point to V14/V15 pair
                        bf              28,novr12                               ; Do not save VR12...
                        stvxl   v12,br0,r22                             ; Save VR12
                        
novr12:
                        bf              29,novr13                               ; Do not save VR13...
                        stvxl   v13,r30,r22                             ; Save VR13
                        
novr13:
                        mtcrf   0x02,r10                                ; Set CRs for registers 24-27
                        la              r20,savevr20(r3)                ; Point to line 10
                        bf              3,nol9                                  ; No line 9 to do...
                        dcba    br0,r21                                 ; Allocate cache line 9
                        
nol9:           
                        la              r22,savevr16(r3)                ; Point to V16/V17 pair
                        bf              30,novr14                               ; Do not save VR14...
                        stvxl   v14,br0,r23                             ; Save VR14
                        
novr14:
                        bf              31,novr15                               ; Do not save VR15...
                        stvxl   v15,r30,r23                             ; Save VR15
                        
novr15:
;
;                       Note: CR7 is now free
;
                        la              r21,savevr22(r3)                ; Point to line 11
                        bf              5,nol10                                 ; No line 10 to do...
                        dcba    br0,r20                                 ; Allocate cache line 10
                        
nol10:          
                        la              r23,savevr18(r3)                ; Point to V18/V19 pair
                        bf              16,novr16                               ; Do not save VR16...
                        stvxl   v16,br0,r22                             ; Save VR16
                        
novr16:
                        bf              17,novr17                               ; Do not save VR17...
                        stvxl   v17,r30,r22                             ; Save VR17
                        
novr17:
                        mtcrf   0x01,r10                                ; Set CRs for registers 28-31
;
;                       Note: All registers have been or are accounted for in CRs
;
                        la              r20,savevr24(r3)                ; Point to line 12
                        bf              7,nol11                                 ; No line 11 to do...
                        dcba    br0,r21                                 ; Allocate cache line 11
                        
nol11:          
                        la              r22,savevr20(r3)                ; Point to V20/V21 pair
                        bf              18,novr18                               ; Do not save VR18...
                        stvxl   v18,br0,r23                             ; Save VR18
                        
novr18:
                        bf              19,novr19                               ; Do not save VR19...
                        stvxl   v19,r30,r23                             ; Save VR19
                        
novr19:
                        la              r21,savevr26(r3)                ; Point to line 13
                        bf              9,nol12                                 ; No line 12 to do...
                        dcba    br0,r20                                 ; Allocate cache line 12
                        
nol12:          
                        la              r23,savevr22(r3)                ; Point to V22/V23 pair
                        bf              20,novr20                               ; Do not save VR20...
                        stvxl   v20,br0,r22                             ; Save VR20
                        
novr20:
                        bf              21,novr21                               ; Do not save VR21...
                        stvxl   v21,r30,r22                             ; Save VR21
                        
novr21:
                        la              r20,savevr28(r3)                ; Point to line 14
                        bf              11,nol13                                ; No line 13 to do...
                        dcba    br0,r21                                 ; Allocate cache line 13
                        
nol13:          
                        la              r22,savevr24(r3)                ; Point to V24/V25 pair
                        bf              22,novr22                               ; Do not save VR22...
                        stvxl   v22,br0,r23                             ; Save VR22
                        
novr22:
                        bf              23,novr23                               ; Do not save VR23...
                        stvxl   v23,r30,r23                             ; Save VR23
                        
novr23:
                        la              r21,savevr30(r3)                ; Point to line 15
                        bf              13,nol14                                ; No line 14 to do...
                        dcba    br0,r20                                 ; Allocate cache line 14
                        
nol14:          
                        la              r23,savevr26(r3)                ; Point to V26/V27 pair
                        bf              24,novr24                               ; Do not save VR24...
                        stvxl   v24,br0,r22                             ; Save VR24
                        
novr24:
                        bf              25,novr25                               ; Do not save VR25...
                        stvxl   v25,r30,r22                             ; Save VR25
                        
novr25:
                        bf              15,nol15                                ; No line 15 to do...
                        dcba    br0,r21                                 ; Allocate cache line 15
                        
nol15:          
;
;                       Note: All cache lines allocated now
;
                        la              r22,savevr28(r3)                ; Point to V28/V29 pair
                        bf              26,novr26                               ; Do not save VR26...
                        stvxl   v26,br0,r23                             ; Save VR26
                        
novr26:
                        bf              27,novr27                               ; Do not save VR27...
                        stvxl   v27,r30,r23                             ; Save VR27
                        
novr27:
                        la              r23,savevr30(r3)                ; Point to V30/V31 pair
                        bf              28,novr28                               ; Do not save VR28...
                        stvxl   v28,br0,r22                             ; Save VR28
                        
novr28:         
                        mfvscr  v27                                             ; Get the VSCR
                        bf              29,novr29                               ; Do not save VR29...
                        stvxl   v29,r30,r22                             ; Save VR29
                        
novr29:         
                        la              r22,savevscr(r3)                ; Point to the VSCR save area
                        bf              30,novr30                               ; Do not save VR30...
                        stvxl   v30,br0,r23                             ; Save VR30
                        
novr30:
                        dcba    br0,r22                                 ; Allocate VSCR savearea
                        bf              31,novr31                               ; Do not save VR31...
                        stvxl   v31,r30,r23                             ; Save VR31
                        
novr31:
                        stvxl   v27,br0,r22                             ; Save the VSCR

                        

/*
 *                      Now check out the current thread and see if we need to load up his context.
 *                      If we do (and this should be the normal case), do it and then release the
 *                      savearea.
 *                      
 *                      If we don't (remember, we already took care of the case where we just enable
 *                      the vector), we need to fill the registers with garbage, because this thread has 
 *                      never used them before and some thieving bastard could hack the old values
 *                      of some thread!  Just imagine what would happen if they could!  Why, nothing
 *                      would be safe! My Gosh! It's terrifying!
 */

vsnosave:       lwz             r15,ACT_MACT_PCB(r17)   ; Get the current level of the "new" one
                        lwz             r14,ACT_MACT_VMX(r17)   ; Point to the top of the "new" context stack
                        lwz             r13,ACT_MACT_VMXlvl(r17)        ; Get the "new" active level

#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F07                               ; (TEST/DEBUG)
                        mr              r1,r15                                  ; (TEST/DEBUG)
                        mr              r3,r14                                  ; (TEST/DEBUG)
                        mr              r5,r13                                  ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#endif  

                        cmplwi  cr1,r14,0                               ; Do we possibly have some context to load?
                        stw             r15,ACT_MACT_VMXlvl(r17)        ; Set the "new" active level
                        la              r23,savevscr(r14)               ; Point to the VSCR
                        stw             r18,ACT_MACT_VMXcpu(r17)        ; Set the active CPU
                        la              r20,savevr0(r14)                ; Point to first line to bring in
                        stw             r17,PP_VMX_THREAD(r6)   ; Store current thread address in vmx_thread to claim vector for thread
                        beq-    cr1,ProtectTheAmericanWay       ; Nothing to restore, first time use...
                        lwz             r0,SAVlvlvec(r14)               ; Get the level of first facility savearea
                        cmplw   r0,r15                                  ; Top level correct to load?
                        bne-    ProtectTheAmericanWay   ; No, go initialize...
                        
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F08                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        mr              r8,r3
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r22,r4                                  ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r22                                  ; Restore it
                        mr              r3,r8
#endif
#endif  

                        li              r0,1                                    ; Get the level invalid indication
                        lwz             r22,savevrsave(r4)              ; Get the most current VRSAVE
                        lwz             r10,savevrvalid(r14)    ; Get the valid VRs in the savearea
                        lis             r9,0x5555                               ; Mask with odd bits set
                        and             r10,r10,r22                             ; Figure out just what registers need to be loaded
                        ori             r9,r9,0x5555                    ; Finish mask
                        rlwinm  r11,r10,1,0,31                  ; Shift over 1
                        stw             r0,SAVlvlvec(r14)               ; Mark the savearea invalid because we are activating again
                        or              r12,r10,r11                             ; After this, even bits show which lines to touch
                        dcbt    br0,r23                                 ; Touch in the VSCR
                        andc    r13,r12,r9                              ; Clear out odd bits
                        
                        la              r20,savevr0(r14)                ; Point to line 0
                        rlwinm  r3,r13,15,0,15                  ; Move line 8-15 flags to high order odd bits
                        la              r21,savevr2(r3)                 ; Point to line 1
                        or              r3,r13,r3                               ; Set the odd bits
                                                                                        ; (bit 0 is line 0, bit 1 is line 8,
                                                                                        ; bit 2 is line 1, bit 3 is line 9, etc.
                        lvxl    v31,br0,r23                             ; Get the VSCR
                        rlwimi  r3,r10,16,16,31                 ; Put vrsave 0 - 15 into positions 16 - 31
                        mtvscr  v31                                             ; Slam the VSCR value
                        mtcrf   255,r3                                  ; Load up the CRs
                        mr              r22,r20                                 ; Start registers off
;       
;                       Load the new vector state
;
                                                
                        bf              0,lnol0                                 ; No line 0 to do...
                        dcbt    br0,r20                                 ; Touch cache line 0
                        
lnol0:          
                        la              r20,savevr4(r14)                ; Point to line 2
                        bf              2,lnol1                                 ; No line 1 to do...
                        dcbt    br0,r21                                 ; Touch cache line 1
                        
lnol1:          
                        la              r21,savevr6(r14)                ; Point to line 3
                        bf              4,lnol2                                 ; No line 2 to do...
                        dcbt    br0,r20                                 ; Touch cache line 2
                        
lnol2:          
                        li              r30,16                                  ; Get offset for odd registers
                        bf              16,lnovr0                               ; Do not restore VR0...
                        lvxl    v0,br0,r22                              ; Restore VR0
                        
lnovr0:         
                        la              r23,savevr2(r14)                ; Point to V2/V3 pair
                        bf              17,lnovr1                               ; Do not restore VR1...
                        lvxl    v1,r30,r22                              ; Restore VR1
                        
lnovr1:
                        la              r20,savevr8(r14)                ; Point to line 4
                        bf              6,lnol3                                 ; No line 3 to do...
                        dcbt    br0,r21                                 ; Touch cache line 3
                        
lnol3:          
                        la              r22,savevr4(r14)                ; Point to V4/V5 pair
                        bf              18,lnovr2                               ; Do not restore VR2...
                        lvxl    v2,br0,r23                              ; Restore VR2
                        
lnovr2:
                        bf              19,lnovr3                               ; Do not restore VR3...
                        lvxl    v3,r30,r23                              ; Restore VR3
                        
lnovr3:
;
;                       Note: CR4 is now free
;
                        la              r21,savevr10(r14)               ; Point to line 5
                        bf              8,lnol4                                 ; No line 4 to do...
                        dcbt    br0,r20                                 ; Touch cache line 4
                        
lnol4:          
                        la              r23,savevr6(r14)                ; Point to R6/R7 pair
                        bf              20,lnovr4                               ; Do not restore VR4...
                        lvxl    v4,br0,r22                              ; Restore VR4
                        
lnovr4:
                        bf              21,lnovr5                               ; Do not restore VR5...
                        lvxl    v5,r30,r22                              ; Restore VR5
                        
lnovr5:
                        mtcrf   0x08,r10                                ; Set CRs for registers 16-19
                        la              r20,savevr12(r14)               ; Point to line 6
                        bf              10,lnol5                                ; No line 5 to do...
                        dcbt    br0,r21                                 ; Touch cache line 5
                        
lnol5:          
                        la              r22,savevr8(r14)                ; Point to V8/V9 pair
                        bf              22,lnovr6                               ; Do not restore VR6...
                        lvxl    v6,br0,r23                              ; Restore VR6
                        
lnovr6:
                        bf              23,lnovr7                               ; Do not restore VR7...
                        lvxl    v7,r30,r23                              ; Restore VR7
                        
lnovr7:
;
;                       Note: CR5 is now free
;
                        la              r21,savevr14(r14)               ; Point to line 7
                        bf              12,lnol6                                ; No line 6 to do...
                        dcbt    br0,r20                                 ; Touch cache line 6
                        
lnol6:          
                        la              r23,savevr10(r14)               ; Point to V10/V11 pair
                        bf              24,lnovr8                               ; Do not restore VR8...
                        lvxl    v8,br0,r22                              ; Restore VR8
                        
lnovr8:
                        bf              25,lnovr9                               ; Do not save VR9...
                        lvxl    v9,r30,r22                              ; Restore VR9
                        
lnovr9:
                        mtcrf   0x04,r10                                ; Set CRs for registers 20-23
                        la              r20,savevr16(r14)               ; Point to line 8
                        bf              14,lnol7                                ; No line 7 to do...
                        dcbt    br0,r21                                 ; Touch cache line 7
                        
lnol7:          
                        la              r22,savevr12(r14)               ; Point to V12/V13 pair
                        bf              26,lnovr10                              ; Do not restore VR10...
                        lvxl    v10,br0,r23                             ; Restore VR10
                        
lnovr10:
                        bf              27,lnovr11                              ; Do not restore VR11...
                        lvxl    v11,r30,r23                             ; Restore VR11
                        
lnovr11:

;
;                       Note: CR6 is now free
;
                        la              r21,savevr18(r14)               ; Point to line 9
                        bf              1,lnol8                                 ; No line 8 to do...
                        dcbt    br0,r20                                 ; Touch cache line 8
                        
lnol8:          
                        la              r23,savevr14(r14)               ; Point to V14/V15 pair
                        bf              28,lnovr12                              ; Do not restore VR12...
                        lvxl    v12,br0,r22                             ; Restore VR12
                        
lnovr12:
                        bf              29,lnovr13                              ; Do not restore VR13...
                        lvxl    v13,r30,r22                             ; Restore VR13
                        
lnovr13:
                        mtcrf   0x02,r10                                ; Set CRs for registers 24-27
                        la              r20,savevr20(r14)               ; Point to line 10
                        bf              3,lnol9                                 ; No line 9 to do...
                        dcbt    br0,r21                                 ; Touch cache line 9
                        
lnol9:          
                        la              r22,savevr16(r14)               ; Point to V16/V17 pair
                        bf              30,lnovr14                              ; Do not restore VR14...
                        lvxl    v14,br0,r23                             ; Restore VR14
                        
lnovr14:
                        bf              31,lnovr15                              ; Do not restore VR15...
                        lvxl    v15,r30,r23                             ; Restore VR15
                        
lnovr15:
;
;                       Note: CR7 is now free
;
                        la              r21,savevr22(r14)               ; Point to line 11
                        bf              5,lnol10                                ; No line 10 to do...
                        dcbt    br0,r20                                 ; Touch cache line 10
                        
lnol10:         
                        la              r23,savevr18(r14)               ; Point to V18/V19 pair
                        bf              16,lnovr16                              ; Do not restore VR16...
                        lvxl    v16,br0,r22                             ; Restore VR16
                        
lnovr16:
                        bf              17,lnovr17                              ; Do not restore VR17...
                        lvxl    v17,r30,r22                             ; Restore VR17
                        
lnovr17:
                        mtcrf   0x01,r10                                ; Set CRs for registers 28-31
;
;                       Note: All registers have been or are accounted for in CRs
;
                        la              r20,savevr24(r14)               ; Point to line 12
                        bf              7,lnol11                                ; No line 11 to do...
                        dcbt    br0,r21                                 ; Touch cache line 11
                        
lnol11:         
                        la              r22,savevr20(r14)               ; Point to V20/V21 pair
                        bf              18,lnovr18                              ; Do not restore VR18...
                        lvxl    v18,br0,r23                             ; Restore VR18
                        
lnovr18:
                        bf              19,lnovr19                              ; Do not restore VR19...
                        lvxl    v19,r30,r23                             ; Restore VR19
                        
lnovr19:
                        la              r21,savevr26(r14)               ; Point to line 13
                        bf              9,lnol12                                ; No line 12 to do...
                        dcbt    br0,r20                                 ; Touch cache line 12
                        
lnol12:         
                        la              r23,savevr22(r14)               ; Point to V22/V23 pair
                        bf              20,lnovr20                              ; Do not restore VR20...
                        lvxl    v20,br0,r22                             ; Restore VR20
                        
lnovr20:
                        bf              21,lnovr21                              ; Do not restore VR21...
                        lvxl    v21,r30,r22                             ; Restore VR21
                        
lnovr21:
                        la              r20,savevr28(r14)               ; Point to line 14
                        bf              11,lnol13                               ; No line 13 to do...
                        dcbt    br0,r21                                 ; Touch cache line 13
                        
lnol13:         
                        la              r22,savevr24(r14)               ; Point to V24/V25 pair
                        bf              22,lnovr22                              ; Do not restore VR22...
                        lvxl    v22,br0,r23                             ; Restore VR22
                        
lnovr22:
                        bf              23,lnovr23                              ; Do not restore VR23...
                        lvxl    v23,r30,r23                             ; Restore VR23
                        
lnovr23:
                        la              r21,savevr30(r14)               ; Point to line 15
                        bf              13,lnol14                               ; No line 14 to do...
                        dcbt    br0,r20                                 ; Touch cache line 14
                        
lnol14:         
                        la              r23,savevr26(r14)               ; Point to V26/V27 pair
                        bf              24,lnovr24                              ; Do not restore VR24...
                        lvxl    v24,br0,r22                             ; Restore VR24
                        
lnovr24:
                        bf              25,lnovr25                              ; Do not restore VR25...
                        lvxl    v25,r30,r22                             ; Restore VR25
                        
lnovr25:
                        bf              15,lnol15                               ; No line 15 to do...
                        dcbt    br0,r21                                 ; Touch cache line 15
                        
lnol15:         
;
;                       Note: All needed cache lines have been touched now
;
                        la              r22,savevr28(r14)               ; Point to V28/V29 pair
                        bf              26,lnovr26                              ; Do not restore VR26...
                        lvxl    v26,br0,r23                             ; Restore VR26
                        
lnovr26:
                        bf              27,lnovr27                              ; Do not restore VR27...
                        lvxl    v27,r30,r23                             ; Restore VR27
                        
lnovr27:
                        la              r23,savevr30(r14)               ; Point to V30/V31 pair
                        bf              28,lnovr28                              ; Do not restore VR28...
                        lvxl    v28,br0,r22                             ; Restore VR28
                        
lnovr28:                
                        bf              29,lnovr29                              ; Do not restore VR29...
                        lvxl    v29,r30,r22                             ; Restore VR29
                        
lnovr29:                
                        bf              30,lnovr30                              ; Do not restore VR30...
                        lvxl    v30,br0,r23                             ; Restore VR30
                        
lnovr30:
;
;                       Everything is restored now except for VR31.  We need it to get
;                       the QNaNBarbarian value to put into idle vector registers
;
                        
                        lis             r5,hi16(EXT(QNaNbarbarian))     ; Get address of empty value
                        cmpwi   r10,-1                                  ; Handle the quick case of all registers in use
                        ori             r5,r5,lo16(EXT(QNaNbarbarian))  ; Get low address of empty value
                        beq-    mstlvr31                                ; Not likely, but all are in use...
                        mtcrf   255,r10                                 ; Get mask of valid registers
                        lvxl    v31,br0,r5                              ; Initialize VR31 to the empty value

                        bt              0,ni0                                   ; Register is ok already...
                        vor             v0,v31,v31                              ; Copy into the next register
ni0:
                        bt              1,ni1                                   ; Register is ok already...
                        vor             v1,v31,v31                              ; Copy into the next register
ni1:
                        bt              2,ni2                                   ; Register is ok already...
                        vor             v2,v31,v31                              ; Copy into the next register
ni2:
                        bt              3,ni3                                   ; Register is ok already...
                        vor             v3,v31,v31                              ; Copy into the next register
ni3:
                        bt              4,ni4                                   ; Register is ok already...
                        vor             v4,v31,v31                              ; Copy into the next register
ni4:
                        bt              5,ni5                                   ; Register is ok already...
                        vor             v5,v31,v31                              ; Copy into the next register
ni5:
                        bt              6,ni6                                   ; Register is ok already...
                        vor             v6,v31,v31                              ; Copy into the next register
ni6:
                        bt              7,ni7                                   ; Register is ok already...
                        vor             v7,v31,v31                              ; Copy into the next register
ni7:
                        bt              8,ni8                                   ; Register is ok already...
                        vor             v8,v31,v31                              ; Copy into the next register
ni8:
                        bt              9,ni9                                   ; Register is ok already...
                        vor             v9,v31,v31                              ; Copy into the next register
ni9:
                        bt              10,ni10                                 ; Register is ok already...
                        vor             v10,v31,v31                             ; Copy into the next register
ni10:
                        bt              11,ni11                                 ; Register is ok already...
                        vor             v11,v31,v31                             ; Copy into the next register
ni11:
                        bt              12,ni12                                 ; Register is ok already...
                        vor             v12,v31,v31                             ; Copy into the next register
ni12:
                        bt              13,ni13                                 ; Register is ok already...
                        vor             v13,v31,v31                             ; Copy into the next register
ni13:
                        bt              14,ni14                                 ; Register is ok already...
                        vor             v14,v31,v31                             ; Copy into the next register
ni14:
                        bt              15,ni15                                 ; Register is ok already...
                        vor             v15,v31,v31                             ; Copy into the next register
ni15:
                        bt              16,ni16                                 ; Register is ok already...
                        vor             v16,v31,v31                             ; Copy into the next register
ni16:
                        bt              17,ni17                                 ; Register is ok already...
                        vor             v17,v31,v31                             ; Copy into the next register
ni17:
                        bt              18,ni18                                 ; Register is ok already...
                        vor             v18,v31,v31                             ; Copy into the next register
ni18:
                        bt              19,ni19                                 ; Register is ok already...
                        vor             v19,v31,v31                             ; Copy into the next register
ni19:
                        bt              20,ni20                                 ; Register is ok already...
                        vor             v20,v31,v31                             ; Copy into the next register
ni20:
                        bt              21,ni21                                 ; Register is ok already...
                        vor             v21,v31,v31                             ; Copy into the next register
ni21:
                        bt              22,ni22                                 ; Register is ok already...
                        vor             v22,v31,v31                             ; Copy into the next register
ni22:
                        bt              23,ni23                                 ; Register is ok already...
                        vor             v23,v31,v31                             ; Copy into the next register
ni23:
                        bt              24,ni24                                 ; Register is ok already...
                        vor             v24,v31,v31                             ; Copy into the next register
ni24:
                        bt              25,ni25                                 ; Register is ok already...
                        vor             v25,v31,v31                             ; Copy into the next register
ni25:
                        bt              26,ni26                                 ; Register is ok already...
                        vor             v26,v31,v31                             ; Copy into the next register
ni26:
                        bt              27,ni27                                 ; Register is ok already...
                        vor             v27,v31,v31                             ; Copy into the next register
ni27:
                        bt              28,ni28                                 ; Register is ok already...
                        vor             v28,v31,v31                             ; Copy into the next register
ni28:
                        bt              29,ni29                                 ; Register is ok already...
                        vor             v29,v31,v31                             ; Copy into the next register
ni29:
                        bt              30,ni30                                 ; Register is ok already...
                        vor             v30,v31,v31                             ; Copy into the next register
ni30:
                        bf              31,lnovr31                              ; R31 is empty, no need to restore...

mstlvr31:       lvxl    v31,r30,r23                             ; Restore VR31
                        
lnovr31:
                        
vrenable:       
                        lwz             r9,SAVflags(r4)                 /* Get the flags of the current savearea */
                        lwz             r8,savesrr1(r4)                 ; Get the msr of the interrupted guy
                        rlwinm  r5,r4,0,0,19                    /* Get the page address of the savearea */
                        oris    r8,r8,hi16(MASK(MSR_VEC))       ; Enable the vector facility
                        lwz             r10,ACT_MACT_SPF(r17)   ; Get the special flags
                        lis             r7,hi16(SAVattach)              /* Get the attached flag */
                        lwz             r5,SACvrswap(r5)                /* Get Virtual to Real translation */
                        oris    r10,r10,hi16(vectorUsed|vectorCng)      ; Set that we used vectors
                        mr.             r15,r15                                 ; See if we are doing this for user state
                        stw             r8,savesrr1(r4)                 ; Set the msr of the interrupted guy
                        andc    r9,r9,r7                                /* Clear the attached bit */
                        xor             r3,r4,r5                                /* Get the real address of the savearea */
                        stw             r9,SAVflags(r4)                 /* Set the flags of the current savearea */
                        bne-    vrnuser                                 ; We are not user state...
                        stw             r10,ACT_MACT_SPF(r17)   ; Set the activation copy
                        stw             r10,spcFlags(r6)                ; Set per_proc copy

vrnuser:
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F0A                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        mr              r8,r3                                   ; Save this
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r3,r8                                   ; Restore it
#endif
#endif  
                        b               EXT(exception_exit)             /* Exit from the fray... */

/*
 *                      Initialize the registers to some bogus value
 *                      We make sure that non-Java mode is the default here
 */

ProtectTheAmericanWay:
                        
#if FPVECDBG
                        lis             r0,HIGH_ADDR(CutTrace)  ; (TEST/DEBUG)
                        li              r2,0x5F09                               ; (TEST/DEBUG)
                        oris    r0,r0,LOW_ADDR(CutTrace)        ; (TEST/DEBUG)
                        sc                                                              ; (TEST/DEBUG)
#if GDDBG
                        lis             r3,hi16(EXT(GratefulDeb))       ; Point to top of display
                        mr              r8,r4                                   ; Save this
                        ori             r3,r3,lo16(EXT(GratefulDeb))    ; Put in bottom part
                        mr              r4,r2                                   ; Set value
                        mtlr    r3                                              ; Set link register
                        li              r3,1                                    ; Display address
                        blrl                                                    ; Display it
                        mr              r4,r8                                   ; Restore it
#endif
#endif  
                        lis             r5,hi16(EXT(QNaNbarbarian))     ; Get address of empty value
                        vspltish v1,1                                   ; Turn on the non-Java bit and saturate
                        ori             r5,r5,lo16(EXT(QNaNbarbarian))  ; Get low address of empty value
                        vspltisw v2,1                                   ; Turn on the saturate bit
                        lvxl    v0,br0,r5                               ; Initialize VR0
                        vxor    v1,v1,v2                                ; Turn off saturate     
                        
                        vor             v2,v0,v0                                ; Copy into the next register
                        mtvscr  v1                                              ; Clear the vector status register
                        vor             v3,v0,v0                                ; Copy into the next register
                        vor             v1,v0,v0                                ; Copy into the next register
                        vor             v4,v0,v0                                ; Copy into the next register
                        vor             v5,v0,v0                                ; Copy into the next register
                        vor             v6,v0,v0                                ; Copy into the next register
                        vor             v7,v0,v0                                ; Copy into the next register
                        vor             v8,v0,v0                                ; Copy into the next register
                        vor             v9,v0,v0                                ; Copy into the next register
                        vor             v10,v0,v0                               ; Copy into the next register
                        vor             v11,v0,v0                               ; Copy into the next register
                        vor             v12,v0,v0                               ; Copy into the next register
                        vor             v13,v0,v0                               ; Copy into the next register
                        vor             v14,v0,v0                               ; Copy into the next register
                        vor             v15,v0,v0                               ; Copy into the next register
                        vor             v16,v0,v0                               ; Copy into the next register
                        vor             v17,v0,v0                               ; Copy into the next register
                        vor             v18,v0,v0                               ; Copy into the next register
                        vor             v19,v0,v0                               ; Copy into the next register
                        vor             v20,v0,v0                               ; Copy into the next register
                        vor             v21,v0,v0                               ; Copy into the next register
                        vor             v22,v0,v0                               ; Copy into the next register
                        vor             v23,v0,v0                               ; Copy into the next register
                        vor             v24,v0,v0                               ; Copy into the next register
                        vor             v25,v0,v0                               ; Copy into the next register
                        vor             v26,v0,v0                               ; Copy into the next register
                        vor             v27,v0,v0                               ; Copy into the next register
                        vor             v28,v0,v0                               ; Copy into the next register
                        vor             v29,v0,v0                               ; Copy into the next register
                        vor             v30,v0,v0                               ; Copy into the next register
                        vor             v31,v0,v0                               ; Copy into the next register
                        b               vrenable                                ; Finish setting it all up...                           

;
;                       Finds a unused vector area in the activation pointed
;                       to by R12s saved contexts.  If none are found (unlikely but possible)
;                       and R3 is 0, a new area is allocated.  If R3 is non-zero, it contains 
;                       a pointer to a vector savearea that is free.
;

vsrchsave:      lwz             r6,ACT_MACT_PCB(r12)            ; Get the first "normal" savearea
                        
vsrnorm:        mr.             r5,r6                                           ; Is there another?
                        beq-    vsrvect                                         ; No, search the floating point saveareas...
                        lwz             r7,SAVflags(r5)                         ; Get the flags for this guy
                        lwz             r6,SAVprev(r5)                          ; Get the previous savearea, just in case
                        andis.  r8,r7,hi16(SAVvmxvalid)         ; Have we found an empty vector save in normal?
                        beq+    vsrgot                                          ; We found one...
                        b               vsrnorm                                         ; Search again...

vsrvect:        lwz             r6,ACT_MACT_FPU(r12)            ; Get the first "floating point" savearea
                        
vsrvectx:       mr.             r5,r6                                           ; Is there another?
                        beq-    vsrget                                          ; No, try to allocate one...
                        lwz             r7,SAVflags(r5)                         ; Get the flags for this guy
                        lwz             r6,SAVprefp(r5)                         ; Get the previous savearea, just in case
                        andis.  r8,r7,hi16(SAVvmxvalid)         ; Have we found an empty vector save in float?
                        bne-    vsrvectx                                        ; Search again...
                        
vsrgot:         mr              r3,r5                                           ; Get the savearea into the right register
                        blr                                                                     ; Return...

vsrget:         mr.             r5,r3                                           ; Do we allocate or use existing?
                        beq+    vsrallo                                         ; Allocate one...
                        
                        lwz             r7,SAVflags(r3)                         ; Get the passed in area flags
                        blr                                                                     ; Return...
;                       
;                       NOTE: save_get will return directly and set R7 to 0...
;
vsrallo:        b               EXT(save_get)                           ; Get a fresh savearea 


/*
 * void lfs(fpsp,fpdp)
 *
 * load the single precision float to the double
 *
 * This routine is used by the alignment handler.
 *
 */
ENTRY(lfs, TAG_NO_FRAME_USED)
        lfs     f1,     0(r3)
        stfd    f1,     0(r4)
        blr

/*
 * fpsp stfs(fpdp,fpsp)
 *
 * store the double precision float to the single
 *
 * This routine is used by the alignment handler.
 *
 */
ENTRY(stfs, TAG_NO_FRAME_USED)
        lfd     f1,     0(r3)
        stfs    f1,     0(r4)
        blr