Source code of Windows XP (NT5)
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230 lines
5.9 KiB

TITLE ISR.ASM -- Windows DLL HARDWARE ISR
;****************************************************************************
;
; PROGRAM: isr.asm
;
; PURPOSE:
; Installs an interrupt handler under Windows 3.x
; This ISR (Interrupt service routine) will then service a requested
; multi-media callback routine.
;
; FUNCTIONS:
; DoInterrupt: Performs interrupt processing
; InstallInterruptHandler: Installs the interrupt handler
; DeInstallInterruptHandler: Removes the interrupt handler
;
;****************************************************************************
.286
memS EQU 1 ;Small memory model
.xlist
include cmacros.inc
include windows.inc
include wowmmcb.inc
include vint.inc
.list
;-------------------------------------------------------------------------;
;
; debug support
;
;-------------------------------------------------------------------------;
externFP OutputDebugString
externFP DoInterrupt
;-------------------------------------------------------------------------;
;
; callback support
;
;-------------------------------------------------------------------------;
externW CodeFixWinFlags
;--------------------------Private-Macro----------------------------------;
; DOUT String - send a debug message to the debugger
;
; Entry:
; String String to send to the COM port, does not need a CR,LF
;
; Registers Destroyed:
; none
;
; NOTE no code is generated unless the DEBUG symbol is defined
;
; History:
; Sun 31-Jul-1989 -by- ToddLa
; Wrote it.
;-------------------------------------------------------------------------;
DOUT macro text
local string_buffer
ifdef MYDEBUG
push cs
push offset string_buffer
call OutputDebugString
jmp @F
string_buffer label byte
db "MMSYSTEM: "
db "&text&",13,10,0
@@:
endif
endm
;****************************************************************************
;
; Create a fixed code segment
;
;****************************************************************************
createSeg FIX, CodeFix, word, public, CODE
createSeg INTDS, DataFix, byte, public, DATA
DOS_SetVector EQU 2500h
DOS_GetVector EQU 3500h
ifdef NEC_98
Pic1 EQU 00h
Pic2 EQU 08h
else ; NEC_98
Pic1 EQU 20h
Pic2 EQU 0a0h
endif ; NEC_98
sBegin Data
staticD dOldVector,0
sEnd
sBegin CodeFix
assumes cs,CodeFix
assumes ds,Data
;****************************************************************************
; FUNCTION: InstallInterruptHandler()
;
; PURPOSE:
; This routine saves the interrupt vector "MultiMediaVector" in
; the global variable "dOldVector". Then, it installs a small
; ISR at that vector which calls the routine "DoInt()" when
; the interrupt occurs.
;
;
;****************************************************************************
cProc InstallInterruptHandler, <FAR,PUBLIC>, <si,di>
cBegin InstallInterruptHandler
push bx ;Save previous vector
push es
mov ax,DOS_GetVector + MULTIMEDIA_INTERRUPT
int 21h
mov WORD PTR dOldVector,bx
mov WORD PTR dOldVector+2,es
pop es
pop bx
push ds ;Install handler
push dx ;
push cs
pop ds
mov dx,OFFSET MULTI_MEDIA_ISR286
test cs:[CodeFixWinFlags],WF_WIN286
jnz @F
mov dx,OFFSET MULTI_MEDIA_ISR386
@@:
mov ax,DOS_SetVector + MULTIMEDIA_INTERRUPT
int 21h
pop dx
pop ds
jmp set_exit
; **** Entry point of ISR ****
MULTI_MEDIA_ISR286: ;Our Multi-Media ISR (286)
pusha
push ds
push es
cCall DoInterrupt ;Do Interrupt Handling
mov al,20h
out Pic2,al ;EOI on Pic2
out Pic1,al ;EOI on Pic1
pop es
pop ds
popa
; FSTI
; iret ;exit MULTI_MEDIA_ISR
FIRET
MULTI_MEDIA_ISR386: ;Our Multi-Media ISR (286)
.386
pushad
push ds
push es
push fs
push gs
cCall DoInterrupt ;Do Interrupt Handling
mov al,20h
out Pic2,al ;EOI on Pic2
out Pic1,al ;EOI on Pic1
pop gs
pop fs
pop es
pop ds
popad
; FSTI
; iret ;exit MULTI_MEDIA_ISR
FIRET
.286
set_exit: ;exit InstallHandler
; DOUT <Interupt installed>
mov ax,1 ;return TRUE
cEnd InstallInteruptHandler
;****************************************************************************
; FUNCTION: DeInstallInterruptHandler()
;
; PURPOSE:
; Restores the interrupt vector "MultiMediaVector" with the address
; at "dOldVector".
;
;****************************************************************************
cProc DeInstallInterruptHandler, <FAR,PUBLIC>, <si,di>
cBegin DeInstallInterruptHandler
push ds ;
push dx ;
mov dx,WORD PTR dOldVector
mov ax,WORD PTR dOldVector+2
cmp dx,0 ;were we installed?
jnz dih_go
cmp ax,0
jz dih_skip
dih_go:
mov ds,ax
mov ax,DOS_SetVector + MULTIMEDIA_INTERRUPT
int 21h
dih_skip:
pop dx ;
pop ds ;
cEnd DeInstallHandler
sEnd
end