osfmk/ppc/Emulate.s

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23         Emulate.s
  24
  25         Emulate instructions and traps.
  26
  27         Lovingly crafted by Bill Angell using traditional methods and only natural or recycled materials.
  28         No animal products are used other than rendered otter bile and deep fried pork lard.
  29
  30 */
  31
  32 #include <cpus.h>
  33 #include <ppc/asm.h>
  34 #include <ppc/proc_reg.h>
  35 #include <ppc/exception.h>
  36 #include <mach/machine/vm_param.h>
  37 #include <assym.s>
  38
  39
  40 ;                       General stuff what happens here:
  41 ;                               1)      All general context saved, interrupts off, translation off
  42 ;                               2)      Vector and floating point disabled, but there may be live context.
  43 ;                                       This code is responsible for saving and restoring what is used. This
  44 ;                                       includes exception states, java mode, etc.
  45 ;                               3)      No attempt is made to resolve page faults.  PTE misses are handled
  46 ;                                       automatically, but actual faults (ala copyin/copyout) are not. If
  47 ;                                       a fault does occur, the exception that caused entry to the emulation
  48 ;                                       routine is remapped to either an instruction or data miss (depending
  49 ;                                       upon the stage detected) and redrived through the exception handler.
  50 ;                                       The only time that an instruction fault can happen is when a different
  51 ;                                       processor removes a mapping between our original fault and when we
  52 ;                                       fetch the assisted instruction. For an assisted instruction, data
  53 ;                                       faults should not occur (except in the MP case).  For a purely
  54 ;                                       emulated instruction, faults can occur.
  55 ;
  56 ;
  57
  58
  59                         .align  5
  60                         .globl  EXT(Emulate)
  61
  62 LEXT(Emulate)
  63
  64                         b               EXT(EmulExit)                                   ; Just return for now...
  65