# # Copyright (c) 1998 Robert Nordier # All rights reserved. # # Redistribution and use in source and binary forms are freely # permitted provided that the above copyright notice and this # paragraph and the following disclaimer are duplicated in all # such forms. # # This software is provided "AS IS" and without any express or # implied warranties, including, without limitation, the implied # warranties of merchantability and fitness for a particular # purpose. # # $Id: btxv86.s,v 1.2 1998/10/22 20:22:07 msmith Exp $ # # BTX V86 interface. # # # Globals. # .global __v86int # # Fields in V86 interface structure. # .set V86_CTL,0x0 # Control flags .set V86_ADDR,0x4 # Int number/address .set V86_ES,0x8 # V86 ES .set V86_DS,0xc # V86 DS .set V86_FS,0x10 # V86 FS .set V86_GS,0x14 # V86 GS .set V86_EAX,0x18 # V86 EAX .set V86_ECX,0x1c # V86 ECX .set V86_EDX,0x20 # V86 EDX .set V86_EBX,0x24 # V86 EBX .set V86_EFL,0x28 # V86 eflags .set V86_EBP,0x2c # V86 EBP .set V86_ESI,0x30 # V86 ESI .set V86_EDI,0x34 # V86 EDI # # Other constants. # .set INT_V86,0x31 # Interrupt number .set SIZ_V86,0x38 # Size of V86 structure # # V86 interface function. # __v86int: popl __v86ret # Save return address pushl $__v86 # Push pointer call __v86_swap # Load V86 registers int $INT_V86 # To BTX call __v86_swap # Load user registers addl $0x4,%esp # Discard pointer pushl __v86ret # Restore return address ret # To user # # Swap V86 and user registers. # __v86_swap: xchgl %ebp,0x4(%esp,1) # Swap pointer, EBP xchgl %eax,V86_EAX(%ebp) # Swap EAX xchgl %ecx,V86_ECX(%ebp) # Swap ECX xchgl %edx,V86_EDX(%ebp) # Swap EDX xchgl %ebx,V86_EBX(%ebp) # Swap EBX pushl %eax # Save pushf # Put eflags popl %eax # in EAX xchgl %eax,V86_EFL(%ebp) # Swap pushl %eax # Put EAX popf # in eflags movl 0x8(%esp,1),%eax # Load EBP xchgl %eax,V86_EBP(%ebp) # Swap movl %eax,0x8(%esp,1) # Save EBP popl %eax # Restore xchgl %esi,V86_ESI(%ebp) # Swap ESI xchgl %edi,V86_EDI(%ebp) # Swap EDI xchgl %ebp,0x4(%esp,1) # Swap pointer, EBP ret # To caller # # V86 interface structure. # .comm __v86,SIZ_V86 .comm __v86ret,4