]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/ppc/Emulate.s
xnu-792.12.6.tar.gz
[apple/xnu.git] / osfmk / ppc / Emulate.s
index 7ce668c5fa8acf073f3181f525dd536b617d7435..a76816a8d977f10032e223491230ed7cbc2336d7 100644 (file)
@@ -1,26 +1,31 @@
 /*
  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
  * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
- * 
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
+ * This file contains Original Code and/or Modifications of Original Code 
+ * as defined in and that are subject to the Apple Public Source License 
+ * Version 2.0 (the 'License'). You may not use this file except in 
+ * compliance with the License.  The rights granted to you under the 
+ * License may not be used to create, or enable the creation or 
+ * redistribution of, unlawful or unlicensed copies of an Apple operating 
+ * system, or to circumvent, violate, or enable the circumvention or 
+ * violation of, any terms of an Apple operating system software license 
+ * agreement.
+ *
+ * Please obtain a copy of the License at 
+ * http://www.opensource.apple.com/apsl/ and read it before using this 
  * file.
- * 
- * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
+ *
+ * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
+ * Please see the License for the specific language governing rights and 
  * limitations under the License.
- * 
- * @APPLE_LICENSE_HEADER_END@
+ *
+ * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  */
 /*                                                                                                                                                                                     
        Emulate.s 
 
 */
 
-#include <cpus.h>
 #include <ppc/asm.h>
 #include <ppc/proc_reg.h>
 #include <ppc/exception.h>
+#include <ppc/cpu_capabilities.h>
 #include <mach/machine/vm_param.h>
 #include <assym.s>
 
-#define kernAccess 31
 #define traceInst 30
 #define dssAllDone 29
 
 
 LEXT(Emulate)
 
+                       bf--    pf64Bitb,emn64                                  ; Skip if not 64-bit
+                       b               EXT(Emulate64)                                  ; Jump to the 64-bit code...
                        
-                       mfsprg  r31,0                                                   ; Get the per_proc
-                       lis             r30,hi16(EXT(dgWork))                   ; Get the high half of diagnostic work area
-                       lwz             r12,savesrr1(r13)                               ; Get the exception info
-                       ori             r30,r30,lo16(EXT(dgWork))               ; And the low half
+emn64:         mfsprg  r31,0                                                   ; Get the per_proc
+                       lwz             r12,savesrr1+4(r13)                             ; Get the exception info
                        rlwinm. r0,r12,0,SRR1_PRG_ILL_INS_BIT,SRR1_PRG_ILL_INS_BIT      ; Emulation candidate?
-                       lwz             r30,dgFlags(r30)                                ; Get the flags
+                       lwz             r30,dgFlags(0)                                  ; Get the flags
                        beq+    eExit                                                   ; Nope, do not try to emulate...
 
                        rlwinm. r0,r30,0,enaDiagEMb,enaDiagEMb  ; Do we want to try to emulate something?
@@ -114,9 +118,9 @@ eNoVect:    bl              eIFetch                                                 ; Get the instruction image
                        cror    cr1_eq,cr1_eq,cr0_eq                    ; Remember
                        bne             cr1_eq,eNotIndex                                ; Go check non-index forms...
 
-                       rlwinm. r21,r10,18,25,29                                ; Extract index to rA to build EA
-                       rlwinm  r22,r10,23,25,29                                ; Extract index to rB
-                       addi    r24,r13,saver0                                  ; Point to the start of registers
+                       rlwinm. r21,r10,19,24,28                                ; Extract index to rA to build EA
+                       rlwinm  r22,r10,24,24,28                                ; Extract index to rB
+                       addi    r24,r13,saver0+4                                ; Point to the start of registers
                        li              r19,0                                                   ; Assume 0 base
                        beq             eZeroBase                                               ; Yes...
                        lwzx    r19,r24,r21                                             ; Get the base register value
@@ -131,15 +135,15 @@ eNotIndex:        cmplwi  r0,725                                                  ; stswi?
                        cror    cr1_eq,cr1_eq,cr0_eq                    ; Remember
                        bne             cr1,eExit                                               ; Not one we handle...
        
-                       rlwinm. r21,r10,18,25,29                                ; Extract index to rA to build EA
-                       addi    r24,r13,saver0                                  ; Point to the start of registers
+                       rlwinm. r21,r10,19,24,28                                ; Extract index to rA to build EA
+                       addi    r24,r13,saver0+4                                ; Point to the start of registers
                        li              r22,0                                                   ; Assume 0 base
                        beq             eFinishUp                                               ; Yes, it is...
                        lwzx    r22,r24,r21                                             ; Get the base register value
                        
 eFinishUp:     stw             r20,savedsisr(r13)                              ; Set the DSISR
                        li              r11,T_ALIGNMENT                                 ; Get the exception code
-                       stw             r22,savedar(r13)                                ; Save the DAR
+                       stw             r22,savedar+4(r13)                              ; Save the DAR
                        stw             r11,saveexception(r13)                  ; Set the exception code
                        b               EXT(AlignAssist)                                ; Go emulate the handler...
 
@@ -156,20 +160,15 @@ eExit:            b               EXT(EmulExit)                                   ; Just return for now...
 
                        .align  5
 
-eIFetch:       lwz             r23,savesrr1(r13)                               ; Get old MSR
+eIFetch:       lwz             r23,savesrr1+4(r13)                             ; Get old MSR
                        mflr    r28                                                             ; Save return
 
                        rlwinm. r22,r23,0,MSR_PR_BIT,MSR_PR_BIT ; Within kernel?
 
                        mfmsr   r30                                                             ; Save the MSR for now
-                       lwz             r23,savesrr0(r13)                               ; Get instruction address
-                       crmove  kernAccess,cr0_eq                               ; Remember if fault was in kernel
-                       li              r25,4                                                   ; Set access length
-                       or              r22,r22,r30                                             ; Add PR to access MSR
+                       lwz             r23,savesrr0+4(r13)                             ; Get instruction address
                        
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-
-                       ori             r22,r22,lo16(MASK(MSR_DR)|MASK(MSR_RI))         ; Set RI onto access MSR
+                       ori             r22,r30,lo16(MASK(MSR_DR)|MASK(MSR_RI))         ; Set RI and DR onto access MSR
 
                        crset   cr0_eq                                                  ; Set this to see if we failed
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
@@ -177,15 +176,10 @@ eIFetch:  lwz             r23,savesrr1(r13)                               ; Get old MSR
                        
                        lwz             r10,0(r23)                                              ; Fetch the instruction
                        
-                       crmove  28,cr0_eq                                               ; Remember if we failed
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       mr              r3,r30                                                  ; Get MSR to load
-                       sc                                                                              ; Get back to supervisor state
-                       
-                       bfl+    kernAccess,aaUnSetSegs                  ; Go set SRs if we are in user and need to
+                       mtmsr   r30                                                             ; Trans and RI off
+                       isync
                        
                        mtlr    r28                                                             ; Restore the LR
-                       crmove  cr0_eq,28                                               ; Set CR0_EQ if the fetch succeeded
                        blr                                                                             ; Return with instruction image in R10
 
 
@@ -194,14 +188,14 @@ eIFetch:  lwz             r23,savesrr1(r13)                               ; Get old MSR
 ;
 
 eRedriveAsISI:
-                       lwz             r6,savesrr1(r13)                                ; Get the srr1 value
+                       lwz             r6,savesrr1+4(r13)                              ; Get the srr1 value
                        lwz             r4,SAVflags(r13)                                ; Pick up the flags
                        li              r11,T_INSTRUCTION_ACCESS                ; Set failing instruction fetch code
                        rlwimi  r6,r1,0,0,4                                             ; Move the DSISR bits to the SRR1
                        oris    r4,r4,hi16(SAVredrive)                  ; Set the redrive bit
                        stw             r11,saveexception(r13)                  ; Set the replacement code
                        stw             r4,SAVflags(r13)                                ; Set redrive request
-                       stw             r6,savesrr1(r13)                                ; Set the srr1 value
+                       stw             r6,savesrr1+4(r13)                              ; Set the srr1 value
                        b               EXT(EmulExit)                                   ; Bail out to handle ISI...
 
 
@@ -228,55 +222,42 @@ eRedriveAsISI:
                        .globl  EXT(AlignAssist)
 
 LEXT(AlignAssist)
-
-#if 0
-                       b               EXT(EmulExit)                                   ; Just return for now...
-#endif
-
-
+                       bf--    pf64Bitb,aan64                                  ; Skip if not 64-bit
+                       b               EXT(AlignAssist64)                              ; Jump to the 64-bit code...
+                       
+aan64:         lwz             r20,savedsisr(r13)                              ; Get the DSISR
+                       li              r0,0                                                    ; Assume we emulate
                        mfsprg  r31,0                                                   ; Get the per_proc
-                       lwz             r20,savedsisr(r13)                              ; Get the DSISR
+                       mtcrf   0x10,r20                                                ; Put instruction ID in CR for later
                        lwz             r21,spcFlags(r31)                               ; Grab the special flags
-                       mtcrf   0x1C,r20                                                ; Put instruction ID in CR for later
+                       stw             r0,savemisc3(r13)                               ; Assume that we emulate ok
+                       mtcrf   0x08,r20                                                ; Put instruction ID in CR for later
                        rlwinm. r0,r21,0,runningVMbit,runningVMbit      ; Are we running a VM?
-                       lwz             r22,savesrr1(r13)                               ; Get the SRR1
+                       mtcrf   0x04,r20                                                ; Put instruction ID in CR for later
+                       lwz             r22,savesrr1+4(r13)                             ; Get the SRR1
                        bne-    aaPassAlong                                             ; We are in a VM, no emulation for alignment exceptions...
-                       rlwinm. r0,r21,0,trapUnalignbit,trapUnalignbit  ; Should we trap alignment exceptions?
+                       lwz             r19,dgFlags(0)                                  ; Get the diagnostics flags
                        crxor   iFloat,iOptype1,iOptype2                ; Set this to 0 if both bits are either 0 or 1
                        mr              r26,r20                                                 ; Save the DSISR
-                       bne-    aaPassAlong                                             ; No alignment exceptions allowed...
                        rlwinm. r0,r22,0,MSR_SE_BIT,MSR_SE_BIT  ; Were we single stepping?
-                       lwz             r23,savedar(r13)                                ; Pick up the address that we want to access
+                       lwz             r23,savedar+4(r13)                              ; Pick up the address that we want to access
                        crnot   traceInst,cr0_eq                                ; Remember if trace is on
-                       rlwinm. r0,r21,0,notifyUnalignbit,notifyUnalignbit      ; Should we notify that an alignment exception happened?
-                       mfsprg  r28,2                                                   ; Get the processor features
-                       crnot   iNotify,cr0_eq                                  ; Remember to tell someone we did this                          
-                       rlwinm. r22,r22,0,MSR_PR_BIT,MSR_PR_BIT ; Did we take the exception in the kernel and isolate PR?
+                       
+                       rlwinm. r0,r19,0,enaNotifyEMb,enaNotifyEMb      ; Should we notify that an alignment exception happened?
                        mfmsr   r30                                                             ; Save the MSR for now
+                       crnot   iNotify,cr0_eq                                  ; Remember to tell someone we did this                          
                        li              r29,emfp0                                               ; Point to work area
                        crxor   iFloat,iFloat,iOptype3                  ; Set true if we have a floating point instruction
-                       or              r22,r22,r30                                             ; Add PR to access MSR
                        dcbz    r29,r31                                                 ; Clear and allocate a cache line for us to work in
-                       rlwinm  r24,r20,2,25,29                                 ; Get displacement to register to update if update form
+                       rlwinm  r24,r20,3,24,28                                 ; Get displacement to register to update if update form
                        rlwimi  r20,r20,24,28,28                                ; Move load/store indication to the bottom of index
-                       ori             r22,r22,lo16(MASK(MSR_DR)|MASK(MSR_RI))         ; Set RI onto access MSR
-                       crmove  kernAccess,cr0_eq                               ; Remember if fault was in kernel
-                       rlwinm. r28,r28,0,pfAltivecb,pfAltivecb ; Do we have Altivec on this machine?
+                       ori             r22,r30,lo16(MASK(MSR_DR)|MASK(MSR_RI))         ; Set RI onto access MSR
                        rlwimi  r20,r20,26,27,27                                ; Move single/double indication to just above the bottom
-                       beq             aaNoVect                                                ; Nope, no Altivec...
-                       
-                       dssall                                                                  ; We need to kill streams because we are going to flip to problem state
-                       sync
-                       
-aaNoVect:      lis             r29,hi16(aaFPopTable)                   ; High part of FP branch table
+                       lis             r29,hi16(EXT(aaFPopTable))              ; High part of FP branch table
                        bf-             iFloat,aaNotFloat                               ; This is not a floating point instruction...
-                       li              r25,8                                                   ; Assume 8-byte access for now
-                       ori             r29,r29,lo16(aaFPopTable)               ; Low part of FP branch table
-                       bt              iDouble,aaFPis8                                 ; So far, we think we are a double...
-                       li              r25,4                                                   ; Set word access
+                       ori             r29,r29,lo16(EXT(aaFPopTable))  ; Low part of FP branch table
                        
-aaFPis8:       rlwimi  r29,r20,0,22,28                                 ; Index into table based upon register||iDouble||iStore
-                       ori             r0,r30,lo16(MASK(MSR_FP))               ; Turn on floating point
+                       rlwimi  r29,r20,0,22,28                                 ; Index into table based upon register||iDouble||iStore
                        mtctr   r29                                                             ; Get set to call the function  
                        bt              iStore,aaFPstore                                ; This is an FP store...
                
@@ -284,11 +265,8 @@ aaFPis8:   rlwimi  r29,r20,0,22,28                                 ; Index into table based upon register||iDou
 ;                      Here we handle floating point loads
 ;                      
 
-aaFPload:      bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-
-                       crset   cr0_eq                                                  ; Set this to see if we failed
-                       ori             r3,r30,lo16(MASK(MSR_FP))               ; We will need FP on in a bit, so turn on when we ditch problem state
-                       mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
+aaFPload:      crset   cr0_eq                                                  ; Set this to see if we failed
+                       mtmsr   r22                                                             ; Flip DR, RI
                        isync
                        
                        lwz             r10,0(r23)                                              ; Get the first word
@@ -297,8 +275,9 @@ aaFPload:   bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
                        lwz             r11,4(r23)                                              ; Get the second half
                        
 aaLdNotDbl:    mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state and turn on FP
+                       
+                       mtmsr   r30                                                             ; Turn off translation again
+                       isync
                        
                        bf-             cr0_eq,aaRedriveAsDSI                   ; Go redrive this as a DSI...   
                        
@@ -315,24 +294,17 @@ aaLdNotDbl:       mr              r4,r0                                                   ; Save the DAR if we failed the access
 
                        .align  5
 
-aaFPstore:     mtmsr   r0                                                              ; We need floating point on for the first phase
-                       isync   
-                       
-                       bctrl                                                                   ; Go save the source FP register
+aaFPstore:     bctrl                                                                   ; Go save the source FP register
                        
                        lwz             r10,emfp0(r31)                                  ; Get first word
                        crandc  iDouble,iDouble,iOptype4                ; Change to 4-byte access if stfiwx
                        lwz             r11,emfp0+4(r31)                                ; and the second
                        bf+             iOptype4,aaNotstfiwx                    ; This is not a stfiwx...
-                       li              r25,4                                                   ; Set this is a word
                        mr              r10,r11                                                 ; The stfiwx wants to store the second half
 
 aaNotstfiwx:
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-                       
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
+                       mtmsr   r22                                                             ; Flip DR, RI
                        isync
                        
                        stw             r10,0(r23)                                              ; Save the first word
@@ -341,31 +313,26 @@ aaNotstfiwx:
                        stw             r11,4(r23)                                              ; Save the second half
                        
 aaStNotDbl:    mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
-                       
+                       mtmsr   r30                                                             ; Turn off
+                       isync
                        
                        bf-             cr0_eq,aaRedriveAsDSI                   ; Go redrive this as a DSI...
-                       
-                       
 
 ;
 ;                      Common exit routines
 ;
 
-aaComExit:     lwz             r10,savesrr0(r13)                               ; Get the failing instruction address
+aaComExit:     lwz             r10,savesrr0+4(r13)                             ; Get the failing instruction address
                        add             r24,r24,r13                                             ; Offset to update register
                        li              r11,T_IN_VAIN                                   ; Assume we are all done
                        addi    r10,r10,4                                               ; Step to the next instruction
                        bf              iUpdate,aaComExNU                               ; Skip if not an update form...
-                       stw             r23,saver0(r24)                                 ; Update the target
+                       stw             r23,saver0+4(r24)                               ; Update the target
                        
 aaComExNU:     lwz             r9,SAVflags(r13)                                ; Get the flags
-                       stw             r10,savesrr0(r13)                               ; Set new PC
+                       stw             r10,savesrr0+4(r13)                             ; Set new PC
                        bt-             traceInst,aaComExitrd                   ; We are tracing, go emulate trace...
                        bf+             iNotify,aaComExGo                               ; Nothing special here, go...
-
-                       bfl+    kernAccess,aaUnSetSegs                  ; Go set SRs if we are in user and need to
        
                        li              r11,T_ALIGNMENT                                 ; Set the we just did an alignment exception....
                        
@@ -375,15 +342,11 @@ aaComExGo:        b               EXT(EmulExit)                                   ; We are done, no tracing on...
 ;
 ;                      This is not a floating point operation
 ;
-;                      The emulation routines for these are positioned every 64 bytes (16 instructions)
-;                      in a 1024-byte aligned table.  It is indexed by taking the low order 4 bits of
+;                      The table of these emulation routines is indexed by taking the low order 4 bits of
 ;                      the instruction code in the DSISR and subtracting 7.  If this comes up negative,
 ;                      the instruction is not to be emulated.  Then we add bit 0 of the code * 4.  This
 ;                      gives us a fairly compact and almost unique index.  Both lwm and stmw map to 0 so
-;                      that one needs to be further reduced, and we end up with holes at index 6, 8, and 10.
-;                      
-;                      If the emulation routine takes more than 16 instructions, it must branch elsewhere
-;                      to finish up.
+;                      that one needs to be further reduced, and we end up with holes at a few indexes.
 ;
 
                        .align  5
@@ -396,7 +359,7 @@ aaNotFloat:
                        ori             r19,r19,lo16(aaEmTable)                 ; Low part of table address
                        blt-    aaPassAlong                                             ; We do not handle any of these (lwarx, stwcx., eciwx, ecowx)...
                        add             r19,r19,r3                                              ; Point to emulation routine
-                       rlwinm  r18,r26,29,25,29                                ; Get the target/source register displacement
+                       rlwinm  r18,r26,30,24,28                                ; Get the target/source register displacement
 
                        mtctr   r19                                                             ; Set the routine address
                        
@@ -404,9 +367,7 @@ aaNotFloat:
 
 ;
 ;                      This is the table of non-floating point emulation routines.
-;                      It is indexed by low 4 bits of DSISR op type - 7 + bit 0 of
-;                      op type * 4
-;
+;                      It is indexed by the code immediately above.
                
                        .align  5                                                       
 
@@ -438,14 +399,12 @@ aaEmTable:
                        .align  5
                                                
 aaLmwStmw:
-                       subfic  r25,r18,32*4                                    ; Calculate the length of the transfer
+                       rlwinm  r17,r18,31,1,29                                 ; Convert doublword based index to words
                        li              r28,0                                                   ; Set no extra bytes to move (used for string instructions)
-                       mr              r17,r25                                                 ; Save the word transfer length here
+                       subfic  r17,r17,32*4                                    ; Calculate the length of the transfer
 
-aaLSComm:      addi    r19,r13,saver0                                  ; Offset to registers in savearea
+aaLSComm:      addi    r19,r13,saver0+4                                ; Offset to registers in savearea
                        mr              r16,r23                                                 ; Make a hunk pointer
-
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
                        
                        bt              iUpdate,aaStmw                                  ; This is the stmw...
                        
@@ -458,7 +417,7 @@ aaLmwNxt:   cmplwi  cr1,r17,8*4                                             ; Is there enough to move 8?
                        subi    r17,r17,8*4                                             ; Back off for another hunk
                        
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
+                       mtmsr   r22                                                             ; Flip DR, RI
                        isync
                
                        lwz             r2,0(r16)                                               ; Load word 0
@@ -478,38 +437,37 @@ aaLmwNxt: cmplwi  cr1,r17,8*4                                             ; Is there enough to move 8?
                        lwz             r9,28(r16)                                              ; Load word 7
                
 aaLmwB1:       mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Turn off DR, RI
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
 
                        addi    r16,r16,8*4                                             ; Point up to next input aread
                
                        stwx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r5,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r6,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r7,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r8,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r9,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
 
                        b               aaLmwNxt                                                ; Do the next hunk...
 
@@ -533,26 +491,25 @@ aaLmwNxtH:        cmplwi  cr1,r17,4*4                                             ; Do we have 4 left?
                        lwz             r5,12(r16)                                              ; Load word 3
                
 aaLmwB2:       mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Turn off DR, RI
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
                
                        addi    r16,r16,4*4                                             ; Point up to next input aread
                        
                        stwx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        stwx    r5,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
 
 aaLmwL4:       or.             r5,r17,r28                                              ; Do we have anything left?
                        cmplwi  cr1,r17,(2*4)                                   ; Do we have one, two, or three full words left?
@@ -602,26 +559,27 @@ aaLmwDn:  rlwinm  r5,r5,24,0,7                                    ; Move first byte to top
                        cmplwi  cr1,r17,(2*4)                                   ; Do we have one, two, or three full words left?
                        mr              r3,r30                                                  ; Set the normal MSR
                        rlwimi  r5,r9,8,8,23                                    ; Move bytes 1 and 2 after 0
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+
+                       mtmsr   r30                                                             ; Turn off DR, RI
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
 
                        beq-    cr2,aaLmwCb                                             ; No full words, copy bytes...
 
                        stwx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        blt             cr1,aaLmwCb                                             ; We only had one, we are done...
                        
                        stwx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        beq             cr1,aaLmwCb                                             ; We had two, we are done...
 
                        stwx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
 
 aaLmwCb:       mr.             r28,r28                                                 ; Any trailing bytes to do?
                        beq+    aaComExit                                               ; Nope, leave...
@@ -644,29 +602,29 @@ aaStmwNxt:        cmplwi  cr1,r17,8*4                                             ; Is there enough to move 8?
                        subi    r17,r17,8*4                                             ; Back off for another hunk
                
                        lwzx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r5,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r6,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r7,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r8,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r9,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        
                        crset   cr0_eq                                                  ; Set this to see if we failed
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
@@ -692,9 +650,8 @@ aaStmwNxt:  cmplwi  cr1,r17,8*4                                             ; Is there enough to move 8?
                
                
 aaStmwB1:      mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Normal MSR
+                       isync
 
                        bt-             cr0_eq,aaStmwNxt                                ; We have more to do and no failed access...
                        b               aaRedriveAsDSI                                  ; We failed, go redrive this as a DSI...
@@ -706,20 +663,20 @@ aaStmwNxtH:       cmplwi  cr1,r17,(4*4)                                   ; Do we have at least 4 left?
                        subi    r17,r17,4*4                                             ; Set count properly
 
                        lwzx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        lwzx    r5,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
+                       mtmsr   r22                                                             ; Flip DR, RI
                        isync
                
                        stw             r2,0(r16)                                               ; Store word 0
@@ -733,9 +690,8 @@ aaStmwNxtH: cmplwi  cr1,r17,(4*4)                                   ; Do we have at least 4 left?
                        addi    r16,r16,4*4                                             ; Point up to next input aread
                
 aaStmwB2:      mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Normal MSR
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
 
@@ -747,18 +703,18 @@ aaStmwL4: or.             r5,r17,r28                                              ; Do we have anything left to do?
                        beq-    cr2,aaStmwBy1                                   ; No full words, check out bytes
 
                        lwzx    r2,r19,r18                                              ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        blt             cr1,aaStmwBy1                                   ; We only had one, go save it...
                        
                        lwzx    r15,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        beq             cr1,aaStmwBy1                                   ; We had two, go save it...
                        
                        lwzx    r14,r19,r18                                             ; Store register
-                       addi    r18,r18,4                                               ; Next register
-                       rlwinm  r18,r18,0,25,29                                 ; Wrap back to 0 if needed
+                       addi    r18,r18,8                                               ; Next register
+                       rlwinm  r18,r18,0,24,28                                 ; Wrap back to 0 if needed
                        
 aaStmwBy1:     mr.             r28,r28                                                 ; Do we have any trailing bytes?
                        beq+    aaStmwSt                                                ; Nope...
@@ -766,22 +722,23 @@ aaStmwBy1:        mr.             r28,r28                                                 ; Do we have any trailing bytes?
                        lwzx    r5,r19,r18                                              ; Yes, pick up one extra register
                        
 aaStmwSt:      crset   cr0_eq                                                  ; Set this to see if we failed
-                       mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
+                       mtmsr   r22                                                             ; Flip DR, RI
                        isync
 
                        beq-    cr2,aaStmwBy2                                   ; No words, check trailing bytes...                                     
 
                        stw             r2,0(r16)                                               ; Save first word
-                       bf-             cr0_eq,aaStmwDn                                 ; Read failed, escape...
+                       bf-             cr0_eq,aaStmwDn                                 ; Store failed, escape...
                        addi    r16,r16,4                                               ; Bump sink
                        blt             cr1,aaStmwBy2                                   ; We only had one, we are done...
 
                        stw             r15,0(r16)                                              ; Save second word
-                       bf-             cr0_eq,aaStmwDn                                 ; Read failed, escape...
+                       bf-             cr0_eq,aaStmwDn                                 ; Store failed, escape...
                        addi    r16,r16,4                                               ; Bump sink
                        beq             cr1,aaStmwBy2                                   ; We had two, we are done...
 
                        stw             r14,0(r16)                                              ; Save third word
+                       bf-             cr0_eq,aaStmwDn                                 ; Store failed, escape...
                        addi    r16,r16,4                                               ; Bump sink
                                
 aaStmwBy2:     rlwinm  r2,r5,8,24,31                                   ; Get byte 0
@@ -804,9 +761,8 @@ aaStmwBy2:  rlwinm  r2,r5,8,24,31                                   ; Get byte 0
                        stb             r14,2(r16)                                              ; Save third byte
 
 aaStmwDn:      mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
-                       mr              r3,r30                                                  ; Set the normal MSR
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Normal MSR
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
 
@@ -819,7 +775,7 @@ aaStmwDn:   mr              r4,r0                                                   ; Remember DAR, jus in case we failed the access
 
                        .align  5
                        
-aaLswx:                lwz             r17,savexer(r13)                                ; Pick up the XER
+aaLswx:                lwz             r17,savexer+4(r13)                              ; Pick up the XER
                        crclr   iUpdate                                                 ; Make sure we think this the load form
                        rlwinm. r25,r17,0,25,31                                 ; Get the number of bytes to load
                        rlwinm  r28,r17,0,30,31                                 ; Get the number of bytes past an even word
@@ -853,7 +809,7 @@ aaLswi:             mr              r9,r23                                                  ; Save the DAR
 
                        .align  5
 
-aaStswx:       lwz             r17,savexer(r13)                                ; Pick up the XER
+aaStswx:       lwz             r17,savexer+4(r13)                              ; Pick up the XER
                        crclr   iUpdate                                                 ; Make sure this is clear in case we have 0 length
                        rlwinm. r25,r17,0,25,31                                 ; Get the number of bytes to load
                        rlwinm  r28,r17,0,30,31                                 ; Get the number of bytes past an even word
@@ -891,28 +847,24 @@ aaStswi:  mr              r9,r23                                                  ; Save the DAR
 
 aaLwbrx:
                        add             r18,r18,r13                                             ; Index to source register
-                       li              r25,4                                                   ; Set the length
-
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
 
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
                        isync
                
                        lwz             r11,0(r23)                                              ; Load the word
                
                        mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
-
+                       mtmsr   r30                                                             ; Restore normal MSR
+                       isync
+                       
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
                        
                        rlwinm  r10,r11,8,0,31                                  ; Get byte 0 to 3 and byte 2 to 1
                        rlwimi  r10,r11,24,16,23                                ; Move byte 1 to byte 2
                        rlwimi  r10,r11,24,0,7                                  ; Move byte 3 to byte 0
                
-                       stw             r10,saver0(r18)                                 ; Set the register
+                       stw             r10,saver0+4(r18)                               ; Set the register
 
                        b               aaComExit                                               ; All done, go exit...
 
@@ -926,26 +878,22 @@ aaLwbrx:
 
 aaStwbrx:
                        add             r18,r18,r13                                             ; Index to source register
-                       li              r25,4                                                   ; Set the length
-                       lwz             r11,saver0(r18)                                 ; Get the register to store
+                       lwz             r11,saver0+4(r18)                               ; Get the register to store
 
                        rlwinm  r10,r11,8,0,31                                  ; Get byte 0 to 3 and byte 2 to 1
                        rlwimi  r10,r11,24,16,23                                ; Move byte 1 to byte 2
                        rlwimi  r10,r11,24,0,7                                  ; Move byte 3 to byte 0
                        
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-                       
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
                        isync
                
                        stw             r10,0(r23)                                              ; Store the reversed halfword
                
                        mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
-
+                       mtmsr   r30                                                             ; Restore normal MSR
+                       isync
+                       
                        bt+             cr0_eq,aaComExit                                ; All done, go exit...
                        b               aaRedriveAsDSI                                  ; We failed, go redrive this as a DSI...        
 
@@ -959,27 +907,23 @@ aaStwbrx:
 
 aaLhbrx:
                        add             r18,r18,r13                                             ; Index to source register
-                       li              r25,2                                                   ; Set the length
-
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
 
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
                        isync
                
                        lhz             r11,0(r23)                                              ; Load the halfword
                
                        mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Restore normal MSR
+                       isync
 
                        bf-             cr0_eq,aaRedriveAsDSI                   ; We failed, go redrive this as a DSI...
                        
                        rlwinm  r10,r11,8,16,23                                 ; Rotate bottom byte up one and clear everything else
                        rlwimi  r10,r11,24,24,31                                ; Put old second from bottom into bottom
                
-                       stw             r10,saver0(r18)                                 ; Set the register
+                       stw             r10,saver0+4(r18)                               ; Set the register
 
                        b               aaComExit                                               ; All done, go exit...
 
@@ -992,23 +936,19 @@ aaLhbrx:
 
 aaSthbrx:
                        add             r18,r18,r13                                             ; Index to source register
-                       li              r25,2                                                   ; Set the length
-                       lwz             r10,saver0(r18)                                 ; Get the register to store
+                       lwz             r10,saver0+4(r18)                               ; Get the register to store
                        rlwinm  r10,r10,8,0,31                                  ; Rotate bottom byte up one
                        rlwimi  r10,r10,16,24,31                                ; Put old second from bottom into bottom
                        
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-                       
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
                        isync
                
                        sth             r10,0(r23)                                              ; Store the reversed halfword
                
                        mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Restore normal MSR
+                       isync
 
                        bt+             cr0_eq,aaComExit                                ; All done, go exit...
                        b               aaRedriveAsDSI                                  ; We failed, go redrive this as a DSI...        
@@ -1019,14 +959,18 @@ aaSthbrx:
 
                        .align  5
 
-aaDcbz:
-                       li              r25,32                                                  ; Set the length
-                       rlwinm  r23,r23,0,0,26                                  ; Round back to a 32-byte boundary
-                       
-                       bfl+    kernAccess,aaSetSegs                    ; Go set SRs if we are in user and need to
-                       
+aaDcbz:                        
+            lwz     r0,savesrr0+4(r13)              ; get instruction address
+            li         r4,_COMM_PAGE_BASE_ADDRESS
+                       rlwinm  r23,r23,0,0,26                                  ; Round EA back to a 32-byte boundary
+            sub     r4,r0,r4                        ; compute instruction offset from base of commpage
+            cmplwi  r4,_COMM_PAGE_AREA_USED         ; did fault occur in commpage?
+            bge+    aaDcbz1                         ; skip if not in commpage
+            lwz                r4,savecr(r13)                  ; if we take a dcbz in the commpage...
+            rlwinm     r4,r4,0,0,27                    ; ...clear users cr7 as a flag for commpage code
+            stw                r4,savecr(r13)
+aaDcbz1:
                        crset   cr0_eq                                                  ; Set this to see if we failed
-                       mr              r3,r30                                                  ; Set the normal MSR
                        li              r0,0                                                    ; Clear this out
                        mtmsr   r22                                                             ; Flip DR, RI, and maybe PR on
                        isync
@@ -1048,8 +992,8 @@ aaDcbz:
                        stw             r0,28(r23)                                              ; Clear word            
                        
 aaDcbzXit:     mr              r4,r0                                                   ; Save the DAR if we failed the access
-                       li              r0,loadMSR                                              ; Set the magic "get back to supervisor" SC
-                       sc                                                                              ; Get back to supervisor state
+                       mtmsr   r30                                                             ; Restore normal MSR
+                       isync
 
                        crclr   iUpdate                                                 ; Make sure we do not think this is an update form
                        
@@ -1061,11 +1005,9 @@ aaDcbzXit:       mr              r4,r0                                                   ; Save the DAR if we failed the access
 ;                      Unhandled alignment exception, pass it along
 ;
 
-aaPassAlongUnMap:
-                       bfl+    kernAccess,aaUnSetSegs                  ; Go set SRs if we are in user and need to
-
-
 aaPassAlong:
+                       li              r0,1                                                    ; Indicate that we failed to emulate
+                       stw             r0,savemisc3(r13)                               ; Assume that we emulate ok
                        b               EXT(EmulExit)                                   
 
 
@@ -1078,7 +1020,6 @@ aaPassAlong:
                        .align  5
                        
 aaComExitrd:
-                       bfl+    kernAccess,aaUnSetSegs                  ; Go set SRs back if we need to because we are not going back to user yet
                        oris    r9,r9,hi16(SAVredrive)                  ; Set the redrive bit
                        li              r11,T_TRACE                                             ; Set trace interrupt
                        rlwinm  r12,r12,0,16,31                                 ; Clear top half of SRR1
@@ -1094,92 +1035,15 @@ aaComExitrd:
 aaRedriveAsDSI:
                        mr              r20,r1                                                  ; Save the DSISR
                        mr              r21,r4
-                       bfl+    kernAccess,aaUnSetSegs                  ; Go set SRs back if we need to because we are not going back to user yet
                        lwz             r4,SAVflags(r13)                                ; Pick up the flags
                        li              r11,T_DATA_ACCESS                               ; Set failing data access code
                        oris    r4,r4,hi16(SAVredrive)                  ; Set the redrive bit
                        stw             r20,savedsisr(r13)                              ; Set the DSISR of failed access
-                       stw             r21,savedar(r13)                                ; Set the address of the failed access
+                       stw             r21,savedar+4(r13)                              ; Set the address of the failed access
                        stw             r11,saveexception(r13)                  ; Set the replacement code
                        stw             r4,SAVflags(r13)                                ; Set redrive request
                        b               EXT(EmulExit)                                   ; Bail out to handle ISI...
 
-;
-;                      Set segment registers for user access.  Do not call this if we are trying to get
-;                      supervisor state memory.  We do not need this.
-;
-;                      Performance-wise, we will usually be setting one SR here. Most memory will be
-;                      allocated before the 1GB mark.  Since the kernel maps the first GB, the exception
-;                      handler always sets the SRs before we get here.  Therefore, we will usually 
-;                      have to remap it.
-;
-;                      Also, we need to un-do these mapping ONLY if we take a non-standard 
-;                      exit, e.g., emulate DSI, emulate trace exception, etc.  This is because
-;                      translation will never be turned on until we return and at that point,
-;                      normal exception exit code will restore the first 4 SRs if needed.
-;
-       
-                       .align  5
-
-                       .globl  EXT(aaSetSegsX)
-
-LEXT(aaSetSegsX)
-                       
-aaSetSegs:     addi    r3,r25,-1                                               ; Point at last accessed offset in range
-                       lwz             r7,PP_USERPMAP(r31)                             ; Get the current user pmap
-                       lis             r0,0x4000                                               ; This is the address of the first segment outside of the kernel
-                       rlwinm  r5,r23,6,26,29                                  ; Get index into pmap table
-                       add             r4,r23,r3                                               ; Point to the last byte accessed
-                       addi    r7,r7,PMAP_SEGS                                 ; Point to the segment slot
-                       cmplw   r23,r0                                                  ; See if first segment register needs to be reloaded
-                       cmplw   cr2,r4,r0                                               ; Do we need to set the second (if any) SR?
-                       xor             r0,r4,r23                                               ; See if we are in the same segment as first
-                       bge             aaSetS1ok                                               ; Nope, we are in a pure user range
-                       
-                       lwzx    r6,r5,r7                                                ; Get the user address space SR value
-                       mtsrin  r6,r23                                                  ; Load the corresponding SR register
-                       
-aaSetS1ok:     rlwinm. r0,r0,0,0,3                                             ; Any change in segment?
-                       bgelr-  cr2                                                             ; We are in user only space, we do not need to mess with SR
-                       rlwinm  r5,r4,6,26,29                                   ; Get index into pmap table
-                       beqlr+                                                                  ; No change in segment, we are done...
-
-                       lwzx    r6,r5,r7                                                ; Get the user address space SR value
-                       mtsrin  r6,r4                                                   ; Load the corresponding SR register
-                       blr                                                                             ; Leave...
-
-;
-;                      Unset segment registers for user access. Do not call unless we had a user access. 
-;
-       
-                       .align  5
-                       
-                       .globl  EXT(aaUnSetSegsX)
-                       
-LEXT(aaUnSetSegsX)
-                       
-aaUnSetSegs:   
-                       addi    r3,r25,-1                                               ; Point at last accessed offset in range
-                       lis             r0,0x4000                                               ; This is the address of the first segment outside of the kernel
-                       lis             r5,hi16(KERNEL_SEG_REG0_VALUE)  ; Get the high half of the kernel SR0 value 
-                       add             r4,r23,r3                                               ; Point to the last byte accessed
-                       cmplw   r23,r0                                                  ; See if first segment register needs to be reloaded
-                       rlwimi  r5,r23,24,8,11                                  ; Make the correct kernel segment
-                       cmplw   cr2,r4,r0                                               ; Do we need to set the second (if any) SR?
-                       xor             r0,r4,r23                                               ; See if we are in the same segment as first
-                       bge             aaUnSetS1ok                                             ; Nope, we are in a pure user range
-                       
-                       mtsrin  r5,r23                                                  ; Load the corresponding SR register
-                       
-aaUnSetS1ok:   
-                       rlwinm. r0,r0,0,0,3                                             ; Any change in segment?
-                       bgelr   cr2                                                             ; We are in user only space, we do not need to mess with SR
-                       rlwimi  r5,r4,24,8,11                                   ; Make the correct kernel segment
-                       beqlr+                                                                  ; No change in segment, we are done...
-
-                       mtsrin  r5,r4                                                   ; Load the corresponding SR register
-                       blr                                                                             ; Leave...
-
 
 
 ;
@@ -1192,8 +1056,9 @@ aaUnSetS1ok:
 ;
 
                        .align  10                                                              ; Make sure we are on a 1k boundary
+                       .globl  EXT(aaFPopTable)
                        
-aaFPopTable:
+LEXT(aaFPopTable)
                        lfs             f0,emfp0(r31)                                   ; Load single variant
                        blr