sys/boot/pc98/btx/lib/btxv86.s

   1 #
   2 # Copyright (c) 1998 Robert Nordier
   3 # All rights reserved.
   4 #
   5 # Redistribution and use in source and binary forms are freely
   6 # permitted provided that the above copyright notice and this
   7 # paragraph and the following disclaimer are duplicated in all
   8 # such forms.
   9 #
  10 # This software is provided "AS IS" and without any express or
  11 # implied warranties, including, without limitation, the implied
  12 # warranties of merchantability and fitness for a particular
  13 # purpose.
  14 #
  15
  16 # $FreeBSD$
  17
  18 #
  19 # BTX V86 interface.
  20 #
  21
  22 #
  23 # Globals.
  24 #
  25                 .global __v86int
  26 #
  27 # Fields in V86 interface structure.
  28 #
  29                 .set V86_CTL,0x0                # Control flags
  30                 .set V86_ADDR,0x4               # Int number/address
  31                 .set V86_ES,0x8                 # V86 ES
  32                 .set V86_DS,0xc                 # V86 DS
  33                 .set V86_FS,0x10                # V86 FS
  34                 .set V86_GS,0x14                # V86 GS
  35                 .set V86_EAX,0x18               # V86 EAX
  36                 .set V86_ECX,0x1c               # V86 ECX
  37                 .set V86_EDX,0x20               # V86 EDX
  38                 .set V86_EBX,0x24               # V86 EBX
  39                 .set V86_EFL,0x28               # V86 eflags
  40                 .set V86_EBP,0x2c               # V86 EBP
  41                 .set V86_ESI,0x30               # V86 ESI
  42                 .set V86_EDI,0x34               # V86 EDI
  43 #
  44 # Other constants.
  45 #
  46                 .set INT_V86,0x31               # Interrupt number
  47                 .set SIZ_V86,0x38               # Size of V86 structure
  48 #
  49 # V86 interface function.
  50 #
  51 __v86int:       popl __v86ret                   # Save return address
  52                 pushl $__v86                    # Push pointer
  53                 call __v86_swap                 # Load V86 registers
  54                 int $INT_V86                    # To BTX
  55                 call __v86_swap                 # Load user registers
  56                 addl $0x4,%esp                  # Discard pointer
  57                 pushl __v86ret                  # Restore return address
  58                 ret                             # To user
  59 #
  60 # Swap V86 and user registers.
  61 #
  62 __v86_swap:     xchgl %ebp,0x4(%esp,1)          # Swap pointer, EBP
  63                 xchgl %eax,V86_EAX(%ebp)        # Swap EAX
  64                 xchgl %ecx,V86_ECX(%ebp)        # Swap ECX
  65                 xchgl %edx,V86_EDX(%ebp)        # Swap EDX
  66                 xchgl %ebx,V86_EBX(%ebp)        # Swap EBX
  67                 pushl %eax                      # Save
  68                 pushf                           # Put eflags
  69                 popl %eax                       #  in EAX
  70                 xchgl %eax,V86_EFL(%ebp)        # Swap
  71                 pushl %eax                      # Put EAX
  72                 popf                            #  in eflags
  73                 movl 0x8(%esp,1),%eax           # Load EBP
  74                 xchgl %eax,V86_EBP(%ebp)        # Swap
  75                 movl %eax,0x8(%esp,1)           # Save EBP
  76                 popl %eax                       # Restore
  77                 xchgl %esi,V86_ESI(%ebp)        # Swap ESI
  78                 xchgl %edi,V86_EDI(%ebp)        # Swap EDI
  79                 xchgl %ebp,0x4(%esp,1)          # Swap pointer, EBP
  80                 ret                             # To caller
  81 #
  82 # V86 interface structure.
  83 #
  84                 .comm __v86,SIZ_V86
  85                 .comm __v86ret,4