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Assembly Source File | 1994-04-25 | 9.5 KB | 382 lines

This is some TASM code for detecting the IRQ and interupt of a Sound Blaster card. Use it well! The Bunny Hunter --------------------------------- Cut Here ------------------------------- WAIT_TIME EQU 000FFh DSP_INTRQ_CMD EQU 000F2h DATA SEGMENT WORD PUBLIC EXTRN SBInt : WORD; EXTRN SBIrq : WORD; ORG_INT2_ADDX DD 0; ORG_INT3_ADDX DD 0; ORG_INT5_ADDX DD 0; ORG_INT7_ADDX DD 0; DATA ENDS CODE SEGMENT WORD PUBLIC ASSUME CS:CODE,DS:DATA ;════════════════════════════════════════════════════════ ; ; ResetDSP - reset the DSP ; ;════════════════════════════════════════════════════════ ResetDSP PROC MOV DX,SBInt ADD DL,6 ; DX = DSP reset port 2x6h MOV AL,1 OUT DX,AL ; write 1, then wait 3 micro-seconds IN AL,DX ; read value from DSP RDSP05: INC AL JNZ RDSP05 ; wait until AL = 0 OUT DX,AL ; write 0 MOV CL,20H ; set reset timeout value RDSP10: CALL ReadDSPTime ; read from DSP CMP AL,0AAH ; if byte is 0AAh then JE RDSP20 ; DSP is reset, exit LOOP RDSP10 ; not reset, try again MOV AX,2 ; set I/O failure error JMP SHORT RDSP90 ; exit; RDSP20: XOR AX,AX ; clear AX, no error RDSP90: OR AX,AX ; set flags for return RET ResetDSP ENDP ;════════════════════════════════════════════════════════ ; ; ReadDSPTime - read from DSP with timeout ; ;════════════════════════════════════════════════════════ ReadDSPTime PROC PUSH CX PUSH DX MOV DX,SBInt ADD DL,0EH ; DX = DSP data available port 2xEh MOV CX,WAIT_TIME ; load timeout value into CX RDT10: IN AL,DX ; check to see if DSP is ready OR AL,AL JS RDT20 ; if sign set, then DSP read ready LOOP RDT10 ; not ready, keep waiting STC ; set error, DSP read timeout JMP SHORT RDT90 ; exit RDT20: SUB DL,4 ; DX = DSP read data port 2xAh IN AL,DX ; read byte from DSP CLC ; clear error RDT90: POP DX POP CX RET ReadDSPTime ENDP ;════════════════════════════════════════════════════════ ; ; CheckSBInt - detect DMA interrupt ; ;════════════════════════════════════════════════════════ PUBLIC CheckSBInt CheckSBInt PROC FAR push bp mov bp,sp MOV AL,2 ; setup end of DMA MOV DX,OFFSET DUMMY_DMA_INT2 ; interrupts for all MOV BX,OFFSET DATA:ORG_INT2_ADDX ; possible IRQs CALL SetupInterrupt ; (2, 3, 5, and 7) MOV AL,3 MOV DX,OFFSET DUMMY_DMA_INT3 MOV BX,OFFSET DATA:ORG_INT3_ADDX CALL SetupInterrupt MOV AL,5 MOV DX,OFFSET DUMMY_DMA_INT5 MOV BX,OFFSET DATA:ORG_INT5_ADDX CALL SetupInterrupt MOV AL,7 MOV DX,OFFSET DUMMY_DMA_INT7 MOV BX,OFFSET DATA:ORG_INT7_ADDX CALL SetupInterrupt MOV SBIrq,0 ; reset current IRQ MOV DX,SBInt ADD DX,0CH ; DX = DSP write port 2xCh MOV AL,DSP_INTRQ_CMD ; AL = interrupt request command CALL WriteDSP ; write command to DSP XOR AX,AX ; assume success MOV CX,WAIT_TIME ; load timeout value into CX CLD VI10: CMP SBIrq,0 ; see if interrupt has been changed JNE VI90 ; if so, continue LOOP VI10 ; if not, keep waiting MOV AX,0FFh ; set DMA failure error VI90: PUSH AX ; save result variable MOV AL,2 ; restore end of DMA MOV BX,OFFSET DATA:ORG_INT2_ADDX ; interrupts CALL RestoreInterrupt MOV AL,3 MOV BX,OFFSET DATA:ORG_INT3_ADDX CALL RestoreInterrupt MOV AL,5 MOV BX,OFFSET DATA:ORG_INT5_ADDX CALL RestoreInterrupt MOV AL,7 MOV BX,OFFSET DATA:ORG_INT7_ADDX CALL RestoreInterrupt POP AX ; restore result OR AX,AX mov sp,bp pop bp RET CheckSBInt ENDP ;════════════════════════════════════════════════════════ ; ; WriteDSP ; ;════════════════════════════════════════════════════════ WriteDSP PROC PUSH CX MOV AH,AL ; save value in AL for later MOV CX,WAIT_TIME WD10: IN AL,DX ; check to see if DSP is ready OR AL,AL JNS WD20 ; if sign set, DSP not write ready LOOP WD10 WD20: MOV AL,AH ; restore AL OUT DX,AL ; send byte to DSP POP CX RET WriteDSP ENDP ;════════════════════════════════════════════════════════ ; ; SetupInterrupt ; ;════════════════════════════════════════════════════════ SetupInterrupt PROC PUSH BX PUSH CX PUSH DX CLI MOV CL,AL ; preserve interrupt number for use ADD AL,8 ; calculate interrupt vector addx CBW SHL AL,1 SHL AL,1 MOV DI,AX PUSH ES ; setup and preserve interrupt XOR AX,AX MOV ES,AX MOV AX,ES:[DI] MOV [BX],AX MOV ES:[DI],DX MOV AX,ES:[DI+2] MOV [BX+2],AX MOV ES:[DI+2],CS POP ES MOV AH,1 ; enable interrupt control mask-bit SHL AH,CL NOT AH IN AL,21H AND AL,AH OUT 21H,AL STI POP DX POP CX POP BX RET SetupInterrupt ENDP ;════════════════════════════════════════════════════════ ; ; RestoreInterrupt ; ; ENTRY: AL = INTERRUPT NUM ; BX = offset to stored addx ; ;════════════════════════════════════════════════════════ RestoreInterrupt PROC CLI MOV CL,AL ADD AL,8 ; calculate interrupt vector addx CBW SHL AL,1 SHL AL,1 MOV DI,AX PUSH ES ; restore interrupt vector XOR AX,AX MOV ES,AX MOV AX,[BX] MOV ES:[DI],AX MOV AX,[BX+2] MOV ES:[DI+2],AX POP ES MOV AH,1 SHL AH,CL IN AL,21H OR AL,AH OUT 21H,AL STI RET RestoreInterrupt ENDP ;════════════════════════════════════════════════════════ ; ; DUMMY INTERRUPTS - used for interrupt detection ; ;════════════════════════════════════════════════════════ DUMMY_DMA_INT2 PROC FAR PUSH DX MOV DX,2 JMP SHORT DUMMY_DMA_ISR DUMMY_DMA_INT2 ENDP DUMMY_DMA_INT3 PROC FAR PUSH DX MOV DX,3 JMP SHORT DUMMY_DMA_ISR DUMMY_DMA_INT3 ENDP DUMMY_DMA_INT5 PROC FAR PUSH DX MOV DX,5 JMP SHORT DUMMY_DMA_ISR DUMMY_DMA_INT5 ENDP DUMMY_DMA_INT7 PROC FAR PUSH DX MOV DX,7 DUMMY_DMA_ISR: PUSH AX PUSH DS MOV AX,DATA MOV DS,AX MOV SBIrq,DX ; update interrupt variable with ; number of interrupt called MOV DX,SBInt ADD DX,0EH ; DX = DSP data available port 2xEh IN AL,DX ; acknowledge DSP interrupt MOV AL,20H ; send EOI (end of interrupt) to OUT 20H,AL ; interrupt controller port 20h POP DS POP AX POP DX IRET ; interrupt return DUMMY_DMA_INT7 ENDP CODE ENDS END