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Assembly Source File | 1994-07-13 | 34.9 KB | 1,735 lines

; PLAYWAV.ASM ; ; Version 1.2 - July 13, 1994. Modified to improve the chip detection ; routine. ; ; This is a program to play .wav files on the Tandy 1000 SL/TL/RL models ; (and other Tandy models) with the built-in DAC. The most common types ; of .wav are playable: 8- or 16-bit mono or stereo, at sampling rates ; up to 65535 Hz. ; ; Syntax: ; PLAYWAV <filename> ; There are no command-line options, and the program doesn't display anything ; on the screen unless there's an error. ; ; This program is based on information contained in the _Tandy 1000TL ; Technical Reference Manual_; the TLSLSND package by Bruce M. Terry, Jr.; ; and the RIFF WAVE file format specification excerpted by Rob Ryan from the ; official Microsoft "Multimedia Programming Interface and Data Specification, ; v.1.0." ; ; This program is in .exe format due to memory requirements greater than ; 64k. ; ; Order of segments: code first. ; SCODE SEGMENT SCODE ENDS ; ; Static data. ; ; Error and debugging messages. ; SDATA SEGMENT NODACMSG DB "Tandy DAC not detected.",0Dh,0Ah,"$" NONAMEERR DB "Must specify input .wav file.",0Dh,0Ah,"$" FOPENERR DB "Open failed on input file.",0Dh,0Ah,"$" READERRMSG DB "Error reading .wav file.",0Dh,0Ah,"$" BADWAVMSG DB ".wav file invalid or unsupported type.",0Dh,0Ah,"$" UNSUPPMSG DB "Unsupported sample size or number of channels in" DB " .wav file.",0Dh,0Ah,"$" UNDERFLOWMSG DB "Output underflow - unable to maintain sampling rate." DB 0Dh,0Ah DB "Copy .wav to hard disk or RAM disk and try again," DB 0Dh,0Ah DB "convert to 8-bit mono, or convert to reduce sampling" DB 0Dh,0Ah,"rate.",0Dh,0Ah,"$" ; ; Default interrupt vectors, for restoring at exit. ; INT1BDEFAULT DD 0 ; ; Default control-C check flag, for restoring at exit. ; CTRLC DB 0 ; ; Flag, indicates .wav type. 0 = 8-bit mono PCM (special ; case, makes fast code). 1 = 8-bit stereo (requires mixing). ; 2 = 16-bit mono (requires conversion to 8-bit). 3 = 16-bit ; stereo (requires mixing and converstion to 8-bit). 4 = ; unsupported type. ; WAVTYPE DW 0 NCHANNELS DW 0 ; number of channels SAMPRATE DW 0 ; sampling rate DMACLOCK DD 3579545 ; DMA clock rate, for computing divider DIVIDER DW 0 ; DAC divider value to match SAMPRATE SAMPLESIZE DW 0 ; bytes per multichannel sample SAMPLES32K DW 0 ; number of multichannel samples in 32k SHIFT DB 0 ; number of shifts to divide by the ; number of bytes in a multichannel ; sample ; ; Flag, 1 = format chunk processed. ; FMTDONE DB 0 ; ; Array of pointers to .wav playing procedures. ; WAVPROCS DW OFFSET MONO8 DW OFFSET STEREO8 DW OFFSET MONO16 DW OFFSET STEREO16 ; ; File handle for .wav file. ; HANDLE DW 0 ; ; Small input buffer and comparison strings for analyzing ; the header. ; HEADERBUF DB 12 DUP (0) RIFFSTR DB "RIFF" ; RIFF signature WAVESTR DB "WAVE" ; WAVE signature FMTSTR DB "fmt " ; format chunk header DATASTR DB "data" ; data chunk header ; ; Pointers to current buffers and full/empty flags. ; CURRENTPLAY DW 0 ; current play buffer FILLSTATUS DB 2 DUP (0) ; 0 = empty; 1 = full LASTBUFFER DB 2 DUP (0) ; 1 = this is the last buffer to play INBUFFER DW 0 ; number of bytes in last buffer filled BUFFERSEGS DW 2 DUP (0) ; buffer segments, initialized at ; runtime, due to assembler bug DONE DB 0 ; 1 = all data has been played SOUNDHALTED DB 0 ; 1 = sound chip finalized after playing ; ; Underflow flag. This flag is set if the output underflows, ; i.e., if the processor does not keep up with the output ; sampling rate. ; UNDERFLOW DB 0 SDATA ENDS ; ; Then the stack. ; STACK SEGMENT STACK DW 512 DUP (?) STACK ENDS ; ; First DMA buffer. ; BUFFER0 SEGMENT DB 32768 DUP (?) BUFFER0 ENDS ; ; Second DMA buffer. ; BUFFER1 SEGMENT DB 32768 DUP (?) BUFFER1 ENDS ; ; File buffer, 128k. Sufficient to load 32768 16-bit ; stereo samples. ; FILEBUFFER SEGMENT DB 32768 DUP (?) FILEBUFFER ENDS FB2 SEGMENT DB 32768 DUP (?) FB2 ENDS FB3 SEGMENT DB 32768 DUP (?) FB3 ENDS FB4 SEGMENT DB 32768 DUP (?) FB4 ENDS SCODE SEGMENT ; ; Interrupt handlers. Default Int 15h vector must be in code segment. ; INT15DEFAULT DD 0 ; ; Control-break handler. Does nothing, disabling control-break. ; INT1BHDLR PROC FAR IRET INT1BHDLR ENDP ; ; Control-C handler. Halts sound output, restores interrupt ; vectors, and terminates the program. ; INT23HDLR PROC FAR MOV AX,SEG SDATA MOV DS,AX CALL HALTSOUND CALL UNHOOK ; ; Restore Int 15h vector to default. ; PUSH DS MOV AX,2515h MOV DX,WORD PTR CS:INT15DEFAULT MOV DS,WORD PTR CS:INT15DEFAULT+2 INT 21h POP DS ; ; Restore control-C check flag. ; MOV AX,3301h MOV DL,CTRLC INT 21h ; ; Terminate (no error). ; MOV AX,4C00h INT 21h INT23HDLR ENDP ; ; Replacement critical error handler. Fails the system ; call (DOS 3.1 and later only). ; INT24HDLR PROC FAR MOV AL,3 IRET INT24HDLR ENDP ; ; First Int 15h handler, for intercepting the BIOS call out ; made when sound output finishes. First, check for the ; magic number indicating end of sound output. ; INT15HDLR1 PROC FAR CMP AX,91FBh JE >L0 JMP DWORD PTR CS:INT15DEFAULT ; ; Finished playing a sound buffer. ; L0: PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI PUSH ES PUSH DS ; ; DS addresses our data, SI is the last buffer played. ; MOV AX,SEG SDATA MOV DS,AX MOV SI,CURRENTPLAY ; ; Check if this is the last buffer. If so, set the done ; flag and exit. ; CMP LASTBUFFER[SI],1 JNE >L1 MOV DONE,1 JMP INT15HDLR1_EXIT ; ; This is not the last buffer. Mark this buffer empty and ; switch play buffers. ; L1: MOV FILLSTATUS[SI],0 XOR SI,1 MOV CURRENTPLAY,SI ; ; If the current play buffer is not full (and ready to play), ; the processor is not keeping up with the output sampling ; rate. Set the done flag and the underflow flag and exit. ; CMP FILLSTATUS[SI],0 JNE >L2 MOV DONE,1 MOV UNDERFLOW,1 JMP INT15HDLR1_EXIT ; ; There is more to play. Start it playing. ; L2: SHL SI,1 MOV AX,BUFFERSEGS[SI] MOV ES,AX XOR BX,BX MOV AX,8307h MOV CX,INBUFFER MOV DX,DIVIDER INT 1Ah ; ; Exit. ; INT15HDLR1_EXIT: POP DS POP ES POP SI POP DX POP CX POP BX POP AX IRET INT15HDLR1 ENDP ; ; Second Int 15h handler. This handler is used (1) before ; the first buffer is played, to make sure the sound chip ; is ready; and (2) on termination, when preparing the sound ; chip for the next application that uses it. ; INT15HDLR2 PROC FAR CMP AX,91FBh JE >L0 JMP DWORD PTR CS:INT15DEFAULT L0: PUSH AX PUSH DS MOV AX,SEG SDATA MOV DS,AX MOV SOUNDHALTED,1 POP DS POP AX IRET INT15HDLR2 ENDP ; ; Subroutines. ; ; Routine to check whether there is BIOS support for Tandy sound functions. ; Sets carry if not. (Modified - July 13, 1994.) ; CHKDAC PROC NEAR PUSH AX PUSH CX ; ; Check for PCMCIA Socket Services. ; MOV AX,8003h XOR CX,CX INT 1Ah CMP CX,5353h JE CHKDAC_NODAC ; ; Check for Tandy DAC. ; MOV AX,8100h INT 1Ah CMP AX,8100h JE CHKDAC_NODAC ; ; DAC found. ; CLC JMP CHKDAC_END CHKDAC_NODAC: STC CHKDAC_END: POP CX POP AX RET CHKDAC ENDP ; ; Routine to hook interrupts needed, other than Int 15h. ; HOOK PROC NEAR PUSH AX PUSH BX PUSH DX PUSH ES ; ; Save default vectors. ; MOV AX,351Bh INT 21h MOV WORD PTR INT1BDEFAULT,BX MOV WORD PTR INT1BDEFAULT+2,ES ; ; Set vectors. ; PUSH DS MOV AX,SEG SCODE MOV DS,AX MOV DX,OFFSET INT1BHDLR MOV AX,251Bh INT 21h MOV DX,OFFSET INT23HDLR MOV AX,2523h INT 21h MOV DX,OFFSET INT24HDLR MOV AX,2524h INT 21h POP DS POP ES POP DX POP BX POP AX RET HOOK ENDP ; ; Routine to unhook interrupts before termination, other than ; Int 15h. ; UNHOOK PROC NEAR PUSH AX PUSH DX PUSH DS MOV DX,WORD PTR INT1BDEFAULT MOV DS,WORD PTR INT1BDEFAULT+2 MOV AX,251Bh INT 21h POP DS POP DX POP AX RET UNHOOK ENDP ; ; Routine to start sound output. ; STARTPLAY PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX PUSH ES ; ; Use the second Int 15h handler now. ; PUSH DS MOV DX,OFFSET INT15HDLR2 MOV AX,SEG SCODE MOV DS,AX MOV AX,2515h INT 21h POP DS ; ; Prepare the sound chip. (Mr. Terry's code.) ; MOV SOUNDHALTED,0 L0: MOV AH,84h INT 1Ah L1: MOV AH,81h INT 1Ah JC L1 CMP SOUNDHALTED,0 JE L0 ; ; Switch to the first Int 15h handler. ; PUSH DS MOV DX,OFFSET INT15HDLR1 MOV AX,SEG SCODE MOV DS,AX MOV AX,2515h INT 21h POP DS ; ; Start playing the first buffer. ; MOV AX,SEG BUFFER0 MOV ES,AX XOR BX,BX MOV CX,INBUFFER MOV DX,DIVIDER MOV AX,8307h INT 1Ah POP ES POP DX POP CX POP BX POP AX RET STARTPLAY ENDP ; ; Routine to halt sound output. Sets up the sound chip for ; the "next" application. ; HALTSOUND PROC NEAR PUSH AX PUSH DX ; ; Use the second Int 15h handler now. ; PUSH DS MOV DX,OFFSET INT15HDLR2 MOV AX,SEG SCODE MOV DS,AX MOV AX,2515h INT 21h POP DS ; ; Finalize the sound chip. (Mr. Terry's code.) ; MOV SOUNDHALTED,0 L0: MOV AH,84h INT 1Ah L1: MOV AH,81h INT 1Ah JC L1 CMP SOUNDHALTED,0 JE L0 POP DX POP AX RET HALTSOUND ENDP ; ; Error handling routine. Display the error message addressed ; by DS:DX, halt sound output, unhook interrupts, and exit the ; program with an errorlevel of 1. Note that DOS will close ; the input file and restore the vectors for Int 23h and Int ; 24h automatically. ; ERROR PROC NEAR MOV AH,9 INT 21h CALL HALTSOUND CALL UNHOOK ; ; Restore Int 15h vector to default. ; PUSH DS MOV AX,2515h MOV DX,WORD PTR CS:INT15DEFAULT MOV DS,WORD PTR CS:INT15DEFAULT+2 INT 21h POP DS ; ; Restore control-C check flag. ; MOV AX,3301h MOV DL,CTRLC INT 21h ; ; Terminate with error. ; MOV AX,4C01h INT 21h ERROR ENDP ; ; Get input filename from the command line, returning its ; address in ES:DX. Assumes that ES addresses the PSP ; on entry. ; GETFILENAME PROC NEAR PUSH AX PUSH CX PUSH DI MOV DI,80h MOV CL,ES:[DI] XOR CH,CH JCXZ GETFILENAME_NONAME INC DI MOV AL,' ' REPE SCASB JE GETFILENAME_NONAME DEC DI INC CX MOV DX,DI REPNE SCASB JNE >L0 DEC DI L0: MOV BYTE PTR ES:[DI],0 POP DI POP CX POP AX RET GETFILENAME_NONAME: MOV DX,OFFSET NONAMEERR CALL ERROR GETFILENAME ENDP ; ; Routine to open the input file. ASCIIZ name passed in ; ES:DX. ; FOPEN PROC NEAR PUSH AX PUSH DS MOV AX,ES MOV DS,AX MOV AX,3D20h ; open read-only, deny writes INT 21h POP DS JNC >L0 MOV DX,OFFSET FOPENERR CALL ERROR L0: MOV HANDLE,AX POP AX RET FOPEN ENDP ; ; Subroutine to read a small number of bytes (specified in ; CX) from the file into HEADERBUF. Returns number of bytes ; in AX, pointer to HEADERBUF in DX. ; READSMALL PROC NEAR PUSH BX MOV AH,3Fh MOV BX,HANDLE MOV DX,OFFSET HEADERBUF INT 21h JC READSMALL_READERR CMP AX,CX JNE READSMALL_INVALID POP BX RET ; ; Error reading .wav file header. ; READSMALL_READERR: MOV DX,OFFSET READERRMSG CALL ERROR ; ; Invalid .wav header, or unsupported .wav type. ; READSMALL_INVALID: MOV DX,OFFSET BADWAVMSG CALL ERROR READSMALL ENDP ; ; Subroutine for GETWAVHEADER. Reads 4 bytes from the input ; file and checks whether the string read is "fmt ", "data", ; another ASCII string, or not ASCII. Returns AL = 0 if ; "fmt ", AL = 1 if "data", AL = -1 if another ASCII string. ; Halts the program if not ASCII. Assumes ES addresses data ; segment. Returns pointer to HEADERBUF in DX. ; GETCHUNK PROC NEAR PUSH BX PUSH CX PUSH SI PUSH DI ; ; Read 4 bytes from the file. ; MOV CX,4 CALL READSMALL ; ; Check if format chunk. ; MOV SI,DX MOV DI,OFFSET FMTSTR REPE CMPSB JNE GETCHUNK_CHKDATA MOV AL,0 JMP GETCHUNK_EXIT ; ; Check if data chunk. ; GETCHUNK_CHKDATA: MOV SI,DX MOV DI,OFFSET DATASTR MOV CX,4 REPE CMPSB JNE GETCHUNK_CHKASCII MOV AL,1 JMP GETCHUNK_EXIT ; ; Check if a valid chunk header of another type. ; GETCHUNK_CHKASCII: MOV SI,DX MOV CX,4 GETCHUNK_ASCLOOP: LODSB CMP AL,20h JB GETCHUNK_INVALID CMP AL,7Eh JA GETCHUNK_INVALID LOOP GETCHUNK_ASCLOOP MOV AL,-1 ; ; Read the chunk length field and exit. ; GETCHUNK_EXIT: PUSH AX MOV CX,4 CALL READSMALL POP AX POP DI POP SI POP CX POP BX RET ; ; Invalid .wav header, or unsupported .wav type. ; GETCHUNK_INVALID: MOV DX,OFFSET BADWAVMSG CALL ERROR GETCHUNK ENDP ; ; Subroutine for GETWAVHEADER. This routine reads the ; format chunk from the file and records the information ; there. Assumes DS:DX addresses chunk length. ; DOFORMAT PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI ; ; Check chunk length (must be 16). ; MOV SI,DX LODSW CMP AX,16 JNE DOFORMAT_INVALID MOV CX,AX LODSW OR AX,AX JNZ DOFORMAT_INVALID ; ; Read in format chunk. ; CALL READSMALL ; ; Verify format tag. ; MOV SI,DX LODSW CMP AX,1 JNE DOFORMAT_INVALID ; ; Verify number of channels and save. ; LODSW CMP AX,1 JE DOFORMAT_CHOK CMP AX,2 JE DOFORMAT_CHOK MOV WAVTYPE,4 JMP DOFORMAT_EXIT DOFORMAT_CHOK: MOV NCHANNELS,AX ; ; Get sampling rate. ; LODSW MOV SAMPRATE,AX LODSW OR AX,AX ; no rate above 65535/sec. JNZ DOFORMAT_INVALID ; ; Get bits per sample. ; ADD SI,6 ; skip bytes/sec, block align LODSW OR AX,AX ; 0-bit samples invalid JZ DOFORMAT_INVALID CMP AX,16 JNA DOFORMAT_BITSOK MOV WAVTYPE,4 ; can't play >16 bit samples JMP DOFORMAT_EXIT ; ; Determine .wav type (0, 1, 2 or 3) and store. ; DOFORMAT_BITSOK: DEC AX SHR AX,1 SHR AX,1 AND AL,2 MOV BX,NCHANNELS DEC BX ADD AX,BX MOV WAVTYPE,AX ; ; Compute divider value for DAC to match sampling rate. ; DOFORMAT_DODIV: MOV BX,SAMPRATE CMP BX,875 JB DOFORMAT_INVALID ; ; Compute divider. Round to nearest. ; MOV AX,WORD PTR DMACLOCK MOV DX,WORD PTR DMACLOCK+2 DIV BX SHR BX,1 CMP BX,DX ADC AX,0 MOV DIVIDER,AX ; ; Exit. ; DOFORMAT_EXIT: POP SI POP DX POP CX POP BX POP AX RET ; ; Invalid .wav header, or unsupported .wav type. ; DOFORMAT_INVALID: MOV DX,OFFSET BADWAVMSG CALL ERROR DOFORMAT ENDP ; ; Subroutine for GETWAVHEADER. This routine skips over an ; unknown chunk, updating the file pointer. Assumes DS:DX ; addresses the chunk length. ; SKIPCHUNK PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI MOV SI,DX LODSW MOV DX,AX LODSW MOV CX,AX MOV AX,4201h MOV BX,HANDLE INT 21h POP SI POP DX POP CX POP BX POP AX RET SKIPCHUNK ENDP ; ; Routine to read the .wav header from the file and compute ; needed parameters, such as the DAC divider value and sample ; size, from it. This version skips unknown chunks. ; GETWAVHEADER PROC NEAR PUSH AX PUSH CX PUSH DX PUSH SI PUSH DI PUSH ES ; ; ES addresses data segment. ; MOV AX,DS MOV ES,AX ; ; Read RIFF and WAVE headers from file. ; MOV CX,12 CALL READSMALL ; ; Verify "RIFF". ; MOV SI,DX MOV DI,OFFSET RIFFSTR MOV CX,4 REPE CMPSB JNE GETWAVHEADER_INVALID ; ; Verify "WAVE". ; ADD SI,4 ; skip length field MOV DI,OFFSET WAVESTR MOV CX,4 REPE CMPSB JNE GETWAVHEADER_INVALID ; ; Loop over chunks until data chunk found. ; GETWAVHEADER_LOOP: CALL GETCHUNK CMP AL,0 ; format chunk? JNE >L0 CMP FMTDONE,1 ; error if > 1 format chunk JE GETWAVHEADER_INVALID CALL DOFORMAT MOV FMTDONE,1 ; mark format done JMP GETWAVHEADER_LOOP L0: CMP AL,1 ; data chunk? JNE >L1 CMP FMTDONE,0 ; error if format chunk does JE GETWAVHEADER_INVALID ; not precede data chunk JMP GETWAVHEADER_LOOPEND L1: CALL SKIPCHUNK ; unknown chunk, skip JMP GETWAVHEADER_LOOP ; ; Data chunk found; skip length field. ; GETWAVHEADER_LOOPEND: MOV CX,4 CALL READSMALL POP ES POP DI POP SI POP DX POP CX POP AX RET ; ; Invalid .wav header, or unsupported .wav type. ; GETWAVHEADER_INVALID: MOV DX,OFFSET BADWAVMSG CALL ERROR GETWAVHEADER ENDP ; ; Routine to play an 8-bit mono .wav. These .wav's require ; no mixing or conversion, so the playing routine can be ; optimized. ; MONO8 PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX PUSH SI ; ; Fill first DMA buffer. ; PUSH DS MOV BX,HANDLE MOV AX,SEG BUFFER0 MOV DS,AX MOV AH,3Fh MOV CX,32768 XOR DX,DX INT 21h POP DS JNC MONO8_CHKEMPTY JMP MONO8_FILEERR ; ; If zero bytes were read, the file contains no samples (an ; unusual case, to say the least). Exit immediately. ; MONO8_CHKEMPTY: OR AX,AX JNZ MONO8_CHKSHORT JMP MONO8_EXIT ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, record the number of bytes in it, ; mark it full, start playing it, and go wait for it to be ; played. This is for a short file with fewer than 32768 ; samples. ; MONO8_CHKSHORT: CMP AX,32768 JE MONO8_NOTSHORT MOV LASTBUFFER,1 MOV INBUFFER,AX MOV FILLSTATUS,1 CALL STARTPLAY JMP MONO8_WAITEND ; ; Not a short file. Record the number of bytes in this ; buffer, mark it full, and start playing it. ; MONO8_NOTSHORT: MOV INBUFFER,AX MOV FILLSTATUS,1 CALL STARTPLAY ; ; Loop, filling buffers when they become empty. SI is the ; current fill buffer. ; MOV SI,1 ; ; First, wait until the current fill buffer becomes empty. ; Halt program with error if underflow is detected. ; MONO8_LOOP: CMP UNDERFLOW,1 JE MONO8_UNDERFLOW CMP FILLSTATUS[SI],0 JNE MONO8_LOOP ; ; Fill buffer. ; PUSH DS MOV BX,HANDLE SHL SI,1 MOV AX,BUFFERSEGS[SI] SHR SI,1 MOV DS,AX MOV AH,3Fh MOV CX,32768 XOR DX,DX INT 21h POP DS JC MONO8_FILEERR ; ; If zero bytes were read, the previous buffer was the last ; buffer. Mark it so and exit the loop. ; OR AX,AX JNZ MONO8_NONZERO XOR SI,1 MOV LASTBUFFER[SI],1 JMP MONO8_WAITEND ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, record the number of bytes in it, ; mark it full, and exit the loop. ; MONO8_NONZERO: CMP AX,32768 JE MONO8_NOTEND MOV LASTBUFFER[SI],1 MOV INBUFFER,AX MOV FILLSTATUS[SI],1 JMP MONO8_WAITEND ; ; This is not the last buffer. Record the number of bytes ; in it, mark it full, switch buffers, and go again. ; MONO8_NOTEND: MOV INBUFFER,AX MOV FILLSTATUS[SI],1 XOR SI,1 JMP MONO8_LOOP ; ; All data has been read. Wait until it's through playing, ; then set up the sound chip for the next application that ; uses it. ; MONO8_WAITEND: CMP DONE,1 JNE MONO8_WAITEND CALL HALTSOUND ; ; Exit. ; MONO8_EXIT: POP SI POP DX POP CX POP BX POP AX RET ; ; Error reading input .wav file. ; MONO8_FILEERR: MOV DX,OFFSET READERRMSG CALL ERROR ; ; Output underflow. ; MONO8_UNDERFLOW: MOV DX,OFFSET UNDERFLOWMSG CALL ERROR MONO8 ENDP ; ; Subroutine for MONO16 and STEREO16 (which call it READ16) ; and STEREO8 (which calls it READ8). This routine reads ; 32768 8-bit stereo or 16-bit samples into the input buffer, ; if possible. Exits program on file error. Returns AX = ; number of samples read. ; READ16 PROC NEAR READ8 EQU READ16 PUSH BX PUSH CX PUSH DX PUSH SI PUSH DI MOV CX,SAMPLESIZE ; CX is read loop counter XOR SI,SI ; SI counts samples read MOV BX,HANDLE ; BX is file handle MOV DI,SEG FILEBUFFER ; DI is current segment XOR DX,DX ; DX is offset (always zero) READ16_LOOP: PUSH CX ; save loop counter PUSH DS ; save DS MOV AH,3Fh ; read into buffer MOV DS,DI MOV CX,32768 INT 21h POP DS ; restore DS JC READ16_ERROR ; exit if file error CMP AX,CX ; if < 32768 bytes read ... JB READ16_EOF ; ... compute samples read ADD SI,SAMPLES32K ; else add constant ADD DI,800h ; go to next 32k segment POP CX ; restore loop counter LOOP READ16_LOOP ; ; End of loop. SI contains samples read. Return in AX. ; READ16_ENDLOOP: MOV AX,SI POP DI POP SI POP DX POP CX POP BX RET ; ; End-of-file encountered. SI contains number of samples ; read, excluding this last read. AX contains number of bytes ; read this time, less than 32k. ; READ16_EOF: POP CX ; clear stack MOV CL,SHIFT SHR AX,CL ADD SI,AX ; add last few samples to count JMP READ16_ENDLOOP ; "rejoin the class" ; ; File error encountered. ; READ16_ERROR: MOV DX,OFFSET READERRMSG CALL ERROR READ16 ENDP ; ; Routine to play an 8-bit stereo .wav. 8-bit .wav's use ; unsigned samples. ; STEREO8 PROC NEAR PUSH AX PUSH BX PUSH CX PUSH SI PUSH DI PUSH ES ; ; Set sample size, samples per 32k, and number of shifts to ; divide by the number of bytes in a sample. ; MOV SAMPLESIZE,2 MOV SAMPLES32K,16384 MOV SHIFT,1 ; ; Fill input buffer. ; CALL READ8 ; ; If zero bytes were read, the file contains no samples (an ; unusual case, to say the least). Exit immediately. ; OR AX,AX JNZ STEREO8_NOTEMPTY JMP STEREO8_EXIT ; ; Save the number of samples. ; STEREO8_NOTEMPTY: MOV INBUFFER,AX ; ; Fill the first DMA buffer. ; PUSH AX PUSH DS MOV CX,AX ; CX counts samples MOV ES,BUFFERSEGS ; ES:DI addresses DMA buffer XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Loop over stereo 8-bit samples. ; STEREO8_LP1: LODSW ; get 2 channels MOV BL,AH XOR AH,AH ADD AL,BL ADC AH,0 ; ; Divide by number of channels (2) and store in DMA buffer. ; SHR AX,1 STOSB LOOP STEREO8_LP1 ; go again if more POP DS POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, mark it full, start playing sound, ; and go wait for it to finish. This is for a short file ; with fewer than 32768 samples. ; CMP AX,32768 JE STEREO8_NOTSHORT MOV LASTBUFFER,1 MOV FILLSTATUS,1 CALL STARTPLAY JMP STEREO8_WAITEND ; ; Start playing. ; STEREO8_NOTSHORT: MOV FILLSTATUS,1 CALL STARTPLAY ; ; Loop, filling buffers when they become empty. SI is the ; current fill buffer. ; MOV SI,1 ; ; First, wait until the current fill buffer becomes empty. ; Halt program with error if underflow is detected. ; STEREO8_LOOP: CMP UNDERFLOW,1 JNE STEREO8_CHKFILLSTAT MOV DX,OFFSET UNDERFLOWMSG CALL ERROR STEREO8_CHKFILLSTAT: CMP FILLSTATUS[SI],0 JNE STEREO8_LOOP ; ; Read in 32k more samples (if possible). ; CALL READ8 ; ; If zero bytes were read, the previous buffer was the last ; buffer. Mark it so and exit the loop. ; OR AX,AX JNZ STEREO8_NONZERO XOR SI,1 MOV LASTBUFFER[SI],1 JMP STEREO8_WAITEND ; ; Save number of samples. ; STEREO8_NONZERO: MOV INBUFFER,AX ; ; Fill the next DMA buffer. ; PUSH AX PUSH SI PUSH DS MOV CX,AX ; CX counts samples SHL SI,1 ; ES:DI addresses DMA buffer MOV ES,BUFFERSEGS[SI] XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Loop over stereo 8-bit samples. ; STEREO8_LP2: LODSW ; get 2 channels MOV BL,AH ; add the two XOR AH,AH ADD AL,BL ADC AH,0 ; ; Divide by number of channels (2) and store in DMA buffer. ; SHR AX,1 STOSB LOOP STEREO8_LP2 ; go again if more POP DS POP SI POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, mark it full, and exit the loop. ; CMP AX,32768 JE STEREO8_NOTEND MOV LASTBUFFER[SI],1 MOV FILLSTATUS[SI],1 JMP STEREO8_WAITEND ; ; This is not the last buffer. Mark it full, switch buffers, ; and go again. ; STEREO8_NOTEND: MOV FILLSTATUS[SI],1 XOR SI,1 JMP STEREO8_LOOP ; ; All data has been read. Wait until it's through playing, ; then set up the sound chip for the next application that ; uses it. ; STEREO8_WAITEND: CMP DONE,1 JNE STEREO8_WAITEND CALL HALTSOUND ; ; Exit. ; STEREO8_EXIT: POP ES POP DI POP SI POP CX POP BX POP AX RET STEREO8 ENDP ; ; Routine to play 16-bit mono .wav's. These use signed ; samples. ; MONO16 PROC NEAR PUSH AX PUSH CX PUSH SI PUSH DI PUSH ES ; ; Set sample size, samples per 32k, and number of shifts to ; divide by the number of bytes in a sample. ; MOV SAMPLESIZE,2 MOV SAMPLES32K,16384 MOV SHIFT,1 ; ; Fill input buffer. ; CALL READ16 ; ; If zero bytes were read, the file contains no samples (an ; unusual case, to say the least). Exit immediately. ; OR AX,AX JNZ MONO16_NOTEMPTY JMP MONO16_EXIT ; ; Save the number of samples. ; MONO16_NOTEMPTY: MOV INBUFFER,AX ; ; Fill the first DMA buffer. ; PUSH AX PUSH DS MOV CX,AX ; CX counts samples MOV ES,BUFFERSEGS ; ES:DI addresses DMA buffer XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Loop over mono 16-bit samples. ; MONO16_LP1: LODSW ; get a sample MOV AL,AH ; convert to 8-bit unsigned ADD AL,128 STOSB ; store in DMA buffer LOOP MONO16_LP1 ; go again if more POP DS POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last. This is for a short file with fewer ; than 32768 samples. ; CMP AX,32768 JE MONO16_NOTSHORT MOV LASTBUFFER,1 MOV FILLSTATUS,1 CALL STARTPLAY JMP MONO16_WAITEND ; ; Start playing. ; MONO16_NOTSHORT: MOV FILLSTATUS,1 CALL STARTPLAY ; ; Loop, filling buffers when they become empty. SI is the ; current fill buffer. ; MOV SI,1 ; ; First, wait until the current fill buffer becomes empty. ; Halt program with error if underflow is detected. ; MONO16_LOOP: CMP UNDERFLOW,1 JE MONO16_UNDERFLOW CMP FILLSTATUS[SI],0 JNE MONO16_LOOP ; ; Read in 32k more samples (if possible). ; CALL READ16 ; ; If zero bytes were read, the previous buffer was the last ; buffer. Mark it so and exit the loop. ; OR AX,AX JNZ MONO16_NONZERO XOR SI,1 MOV LASTBUFFER[SI],1 JMP MONO16_WAITEND ; ; Save number of samples. ; MONO16_NONZERO: MOV INBUFFER,AX ; ; Fill the next DMA buffer. ; PUSH AX PUSH SI PUSH DS MOV CX,AX ; CX counts samples SHL SI,1 ; ES:DI addresses DMA buffer MOV ES,BUFFERSEGS[SI] XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Loop over mono 16-bit samples. ; MONO16_LP2: LODSW ; get a sample MOV AL,AH ADD AL,128 ; convert to unsigned STOSB ; place in DMA buffer LOOP MONO16_LP2 ; go again if more POP DS POP SI POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, mark it full, and exit the loop. ; CMP AX,32768 JE MONO16_NOTEND MOV LASTBUFFER[SI],1 MOV FILLSTATUS[SI],1 JMP MONO16_WAITEND ; ; This is not the last buffer. Mark it full, switch buffers, ; and go again. ; MONO16_NOTEND: MOV FILLSTATUS[SI],1 XOR SI,1 JMP MONO16_LOOP ; ; All data has been read. Wait until it's through playing, ; then set up the sound chip for the next application that ; uses it. ; MONO16_WAITEND: CMP DONE,1 JNE MONO16_WAITEND CALL HALTSOUND ; ; Exit. ; MONO16_EXIT: POP ES POP DI POP SI POP CX POP AX RET ; ; Output underflow. ; MONO16_UNDERFLOW: MOV DX,OFFSET UNDERFLOWMSG CALL ERROR MONO16 ENDP ; ; Routine to play 16-bit stereo .wav's. These use signed ; samples and require mixing. ; STEREO16 PROC NEAR PUSH AX PUSH BX PUSH CX PUSH SI PUSH DI PUSH BP PUSH ES ; ; Set sample size, samples per 32k, and number of shifts to ; divide by the number of bytes in a sample. ; MOV SAMPLESIZE,4 MOV SAMPLES32K,8192 MOV SHIFT,2 ; ; Fill input buffer. ; CALL READ16 ; ; If zero bytes were read, the file contains no samples (an ; unusual case, to say the least). Exit immediately. ; OR AX,AX JNZ STEREO16_NOTEMPTY JMP STEREO16_EXIT ; ; Save the number of samples. ; STEREO16_NOTEMPTY: MOV INBUFFER,AX ; ; Fill the first DMA buffer. ; PUSH AX PUSH DS MOV CX,AX ; CX counts samples MOV ES,BUFFERSEGS ; ES:DI addresses DMA buffer XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Set CX to a maximum of 16k, BP to the remainder of what ; CX was. ; XOR BP,BP CMP CX,16384 JBE STEREO16_LP1 MOV BP,CX MOV CX,16384 SUB BP,CX ; ; Loop over stereo 16-bit samples. ; STEREO16_LP1: LODSW ; get first channel MOV AL,AH CBW MOV BX,AX ; save in BX LODSW ; get second channel MOV AL,AH CBW ADD AX,BX ; add into AX ; ; Divide by number of channels (2), convert to unsigned, and ; store in DMA buffer. ; SAR AX,1 ADD AX,128 STOSB LOOP STEREO16_LP1 ; go again if more MOV CX,BP JCXZ STEREO16_LP1END XOR BP,BP MOV AX,DS ADD AH,10h MOV DS,AX JMP STEREO16_LP1 STEREO16_LP1END: POP DS POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last. This is for a short file with fewer ; than 32768 samples. ; CMP AX,32768 JE STEREO16_NOTSHORT MOV LASTBUFFER,1 MOV FILLSTATUS,1 CALL STARTPLAY JMP STEREO16_WAITEND ; ; Start playing. ; STEREO16_NOTSHORT: MOV FILLSTATUS,1 CALL STARTPLAY ; ; Loop, filling buffers when they become empty. SI is the ; current fill buffer. ; MOV SI,1 ; ; First, wait until the current fill buffer becomes empty. ; Halt program with error if underflow is detected. ; STEREO16_LOOP: CMP UNDERFLOW,1 JNE STEREO16_CHKFILLSTAT MOV DX,OFFSET UNDERFLOWMSG CALL ERROR STEREO16_CHKFILLSTAT: CMP FILLSTATUS[SI],0 JNE STEREO16_LOOP ; ; Read in 32k more samples (if possible). ; CALL READ16 ; ; If zero bytes were read, the previous buffer was the last ; buffer. Mark it so and exit the loop. ; OR AX,AX JNZ STEREO16_NONZERO XOR SI,1 MOV LASTBUFFER[SI],1 JMP STEREO16_WAITEND ; ; Save number of samples. ; STEREO16_NONZERO: MOV INBUFFER,AX ; ; Fill the next DMA buffer. ; PUSH AX PUSH SI PUSH DS MOV CX,AX ; CX counts samples SHL SI,1 ; ES:DI addresses DMA buffer MOV ES,BUFFERSEGS[SI] XOR DI,DI MOV AX,SEG FILEBUFFER ; DS:SI addresses sample data MOV DS,AX XOR SI,SI ; ; Set CX to a maximum of 16k, BP to the remainder of what ; CX was. ; XOR BP,BP CMP CX,16384 JBE STEREO16_LP2 MOV BP,CX MOV CX,16384 SUB BP,CX ; ; Loop over stereo 16-bit samples. ; STEREO16_LP2: LODSW ; get first channel MOV AL,AH CBW MOV BX,AX ; save in BX LODSW ; get second channel MOV AL,AH CBW ADD AX,BX ; add into AX ; ; Divide by number of channels (2), convert to unsigned, and ; store in DMA buffer. ; SAR AX,1 ADD AX,128 STOSB LOOP STEREO16_LP2 ; go again if more MOV CX,BP JCXZ STEREO16_LP2END XOR BP,BP MOV AX,DS ADD AH,10h MOV DS,AX JMP STEREO16_LP2 STEREO16_LP2END: POP DS POP SI POP AX ; ; If fewer than 32768 (but more than zero) bytes were read, ; mark this buffer last, mark it full, and exit the loop. ; CMP AX,32768 JE STEREO16_NOTEND MOV LASTBUFFER[SI],1 MOV FILLSTATUS[SI],1 JMP STEREO16_WAITEND ; ; This is not the last buffer. Mark it full, switch buffers, ; and go again. ; STEREO16_NOTEND: MOV FILLSTATUS[SI],1 XOR SI,1 JMP STEREO16_LOOP ; ; All data has been read. Wait until it's through playing, ; then set up the sound chip for the next application that ; uses it. ; STEREO16_WAITEND: CMP DONE,1 JNE STEREO16_WAITEND CALL HALTSOUND ; ; Exit. ; STEREO16_EXIT: POP ES POP BP POP DI POP SI POP CX POP BX POP AX RET STEREO16 ENDP ; ; Main program. ; MAIN PROC FAR ; ; DS addresses data segment (always; if any routine changes ; DS, it must restore it before returning). ; MOV AX,SEG SDATA MOV DS,AX ; ; Initialize BUFFERSEGS. ; MOV BUFFERSEGS,SEG BUFFER0 MOV BUFFERSEGS+2,SEG BUFFER1 ; ; Direction set to increment (always; if any routine changes ; DF, it must restore it before returning). ; CLD ; ; Check whether the needed sound circuitry is present. ; CALL CHKDAC JNC HOOKVECS MOV DX,OFFSET NODACMSG MOV AH,9 INT 21h JMP TERMINATE ; ; Hook needed interrupt vectors, other than Int 15h. ; HOOKVECS: CALL HOOK ; ; Save default Int 15h vector in code segment. ; PUSH ES ; save PSP for GETFILENAME MOV AX,3515h INT 21h MOV WORD PTR CS:INT15DEFAULT,BX MOV WORD PTR CS:INT15DEFAULT+2,ES POP ES ; restore PSP ; ; Save the control-C check flag status, then turn it on so ; that the user can interrupt playing with <cntrl>-C. ; MOV AX,3300h INT 21h MOV CTRLC,DL MOV AX,3301h MOV DL,1 INT 21h ; ; Open the input file. ; CALL GETFILENAME CALL FOPEN ; ; Get and process the .wav header. ; CALL GETWAVHEADER ; ; Play the .wav. ; MOV BX,WAVTYPE CMP BX,4 JAE BADTYPE SHL BX,1 CALL WAVPROCS[BX] JMP PLAYDONE BADTYPE: MOV DX,OFFSET UNSUPPMSG MOV AH,9 ; .wav has unsupported sample size or INT 21h ; number of channels ; ; Unhook interrupts, other than Int 15h. ; PLAYDONE: CALL UNHOOK ; ; Restore Int 15h vector to default. ; PUSH DS MOV AX,2515h MOV DX,WORD PTR CS:INT15DEFAULT MOV DS,WORD PTR CS:INT15DEFAULT+2 INT 21h POP DS ; ; Restore control-C check flag. ; MOV AX,3301h MOV DL,CTRLC INT 21h ; ; Terminate. ; TERMINATE: MOV AX,4C00h INT 21h MAIN ENDP SCODE ENDS END MAIN