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