/
Asm.S
194 lines (180 loc) · 4.25 KB
/
Asm.S
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/*** M2000: Portable P2000 emulator *****************************************/
/*** ***/
/*** Asm.S ***/
/*** ***/
/*** This file contains MS-DOS specific assembler routines ***/
/*** ***/
/*** Copyright (C) Marcel de Kogel 1996,1997 ***/
/*** You are not allowed to distribute this software commercially ***/
/*** Please, notify me, if you make any changes to this file ***/
/****************************************************************************/
.file "Asm.S"
.data
.align 4
DisplayStart: .long 0xA0000
TimerCount: .long 0
OldInt8: .long 0
OldInt8Selector:.word 0
.globl _DosSelector
.globl _cs_alias
.text
.globl _nofunc
_nofunc:
ret
.globl ___enable
___enable:
sti
ret
.globl ___disable
___disable:
cli
ret
.globl _JoyGetPos
_JoyGetPos:
pushl %ebx
pushl %ecx
pushl %edx
pushl %esi
pushl %edi
movw $0x201,%dx
movl $10000,%ecx
subl %esi,%esi
subl %edi,%edi
cli
outb %al,%dx
jmp _JoyGetPos_Loop
_JoyGetPos_Loop:
inb %dx,%al
movl %eax,%ebx
shrl $1,%ebx
adcl $0,%esi
shrl $1,%ebx
adcl $0,%edi
testb $3,%al
loopnz _JoyGetPos_Loop
sti
movl %edi,%eax
shll $16,%eax
movw %si,%ax
popl %edi
popl %esi
popl %edx
popl %ecx
popl %ebx
ret
.globl _ReadTimer
_ReadTimer:
pushl %edi
pushl %esi
pushl %edx
pushl %ecx
pushl %ebx
movl $50,%ecx
ReadTimer_Loop:
call _nofunc
loop ReadTimer_Loop
ReadTimer_Again:
movl (TimerCount),%eax
shll $16,%eax
outb %al,$0x43
jmp ReadTim1
ReadTim1:
jmp ReadTim2
ReadTim2:
inb $0x40,%al
jmp ReadTim3
ReadTim3:
jmp ReadTim4
ReadTim4:
movb %al,%ah
inb $0x40,%al
xchgb %al,%ah
notw %ax
movl (TimerCount),%ebx
shll $16,%ebx
movw %ax,%bx
cmpl %eax,%ebx
jne ReadTimer_Again
popl %ebx
popl %ecx
popl %edx
popl %esi
popl %edi
ret
timer_interrupt:
pushl %eax
pushw %ds
.byte 0x2e
movw _cs_alias,%ax
movw %ax,%ds
incl (TimerCount)
pushfl
lcall (OldInt8)
popw %ds
popl %eax
iret
install_timer_int:
pushal
movl $0x204,%eax
movb $8,%bl
int $0x31
movl %edx,OldInt8
movw %cx,OldInt8Selector
movw %cs,%cx
leal timer_interrupt,%edx
movb $8,%bl
movl $0x205,%eax
int $0x31
popal
ret
restore_timer_int:
pushal
movl OldInt8,%edx
movw OldInt8Selector,%cx
movb $8,%bl
movl $0x205,%eax
int $0x31
popal
ret
.globl _StartTimer
_StartTimer:
pushl %eax
cli
movb $0x34,%al
outb %al,$0x43
jmp StartTim1
StartTim1:
jmp StartTim2
StartTim2:
subb %al,%al
outb %al,$0x40
jmp StartTim3
StartTim3:
jmp StartTim4
StartTim4:
outb %al,$0x40
sti
call install_timer_int
popl %eax
ret
.globl _RestoreTimer
_RestoreTimer:
pushl %eax
cli
movb $0x36,%al
outb %al,$0x43
jmp ResTim1
ResTim1:
jmp ResTim2
ResTim2:
subb %al,%al
outb %al,$0x40
jmp ResTim3
ResTim3:
jmp ResTim4
ResTim4:
outb %al,$0x40
sti
call restore_timer_int
popl %eax
ret