Programming the Sound Blaster for

 

My Job : program the sound code...

What I did :

Coded Sound portion of program entirely from scratch. Wrote Several Test Programs

 

1. Two Buffers Were used
1. Used a FIFO / Queue for buffering data between a data stream (from network, microphone, or file)
2. Used a Page aligned double buffer for DMA transfers to the Sound Card
2. Program Flow Directed by Interrupts and SoundService
1. Interrupts were used to x-fer data between FIFO and DMA-Buffer
2. Service routines were used to direct data from other sources to FIFO, and to start, stop, and reconfigure initial playing and recording
3. Other sources could also directly write/read from FIFO independently from the DMA x-fers

• Interrupt Handling above 07h and programming both PICs
• Getting the sound card to do anything at all
• Setting up Auto-Init DMA transfers, and especially testing them
• Figuring out how to implement the buffering and data streaming
• Figuring out the differences between SBP and SB16 and other sound hardware
• Finding detailed documentation and reading the minds of the hardware manufacturers

 

Procedures and Macros

SBP_MixerRead	Reads from the mixer data port on the sound card   al -> data read
SBP_MixerWrite	Writes to the mixer data port on the sound card   bl <- data to write
SBP_WaitRead	Polls the sound card to see if it is ready to be Read from
SBP_WaitWrite	polls the Sound Cards status register to see if it is ready   to be written to
	SoundBuffer FIFO routines
BufGetSndReadAddr	This returns the offset address that can be read from   (used for playing by SBP routiens)   (used for recording or saving to disk or net by others)  si -> returned with offset  cx -> amount of data in the buffer that can be read
BufGetSndWriteAddr	This returns the offset address that can be written to   (used for recording by SBP routiens)   (used for moving data that is going to be played by other routiens)  di -> returned with offset  cx -> max amount you can write
BufReadSndData	Reads Sound data from SBP_buf to SoundBuf,   (used for recording by SBP routiens)   (used for moving data that is going to be played by other routiens)  ;   ax <- number bytes to xfer   dx:[si] <- Start Of SBP_Buf or other location,      offset of location to read from      must be one continuous block (cannot overflow)   es:[di] == Start of SoundBuf, offset of WriteAddr   ax -> total data in buffer   bl -> 0 if not over flow, 1 if overflow
BufWriteSndData	Reads Sound data from SoundBuf to SBP_buf or someplace else,   (used for playing by SBP routiens)     (used for recording or saving to disk or net by others)   ax <- number bytes to xfer   es:[di] <- Start Of SBP_Buf or other location,      offset of location to read from      must be one continuous block (cannot overflow)   ds:[si] == Start of SoundBuf, offset of ReadAddr   ax -> total data in buffer   bl -> 0 if not over flow, 1 if overflow
BufSetup	Sets up the two buffers used to set up sound x-fers    ie. (SoundBuf, and SBP_Buf)
BufReset	Resets the Sound Buffer to an intially empty state
BufferMode	Used for finding out what mode SoundBuf is in   al <- BufMode STOP 0, PLAY 1, REC 2
DMA_Setup	Sets up a DMA transfer for a specifed DMA   Heavily adapted and reprogrammed from GPE {dma_vla.txt}     basically new code
SBP_ResetDSP	Resets the DSP on the Sound Blaster Pro/16   note : mic is set to zero volume to kill feedback
SBP_GetSettings	Polls SBP16 PnP settings,    if SB16 isn't there default setting are used   later can change config for different settings
SBP_InstallINT	Installs the Sound Card's interrupt handeler
SBP_INThandler	The Sound Card's interrupt handeler
SBP_UninstallINT	UnInstalls the Sound Card's interrupt handeler
SBP_SetSampleRate	Sets or Resets the sound cards sample rate which is held   in the Variable SBP_RATE   SBP_RATE <- rate to play at or time const (if not SB16
SBP_WriteDSPCmd	writes at byte (Low, High) to DSP   al <- command   bx <- data
{SoundSetup}	Initalized the sound card and sets up the ISR proc
{SoundDestroy}	Cleans up after the sound card when the program exits
{SoundService}	This should be called fairlly frequently so buffers   can be updtated if needed, needed for playing WAVs   or for starting new SoundPlays from other programs
{SoundPlayFlag}	Used to tell SoundService Routien that main program   would like to start playing as soon as the SoundBuf   has enough data in it
{SoundPlay}	starts outputting sound for avialable data in SoundBuff   sound stops when output buffer is empty
SoundPlayCont	called by Sound Interrupt to continue outputting sound   sound stopps when output buffer is empty
SoundPlayEnd	Outputs sound of last part of SoundBuffer via the interrupt
{SoundPlayWav}	Starts playing a WAVE file. to continue playing the file   SoundService must be called enough to reload the buffer   ds:[dx] <- pointer to ASCIIZ string
SoundPlayWavCont	called only from SoundService when a wave file is in the   process of being played, copies new data to buffer
{SoundRec}	Inputs sound via the interrupt until SoundBuffer is full   or a SoundRecStop is called
SoundRecCont	Called by Interrupt to continue REC
{SoundScope}	Shows a nifty sound scope, write to a block of memory   asummes video mode is in 8 bits/pix mode   ax <- ah = background color, al = forground color   bx <- cols (horizontal)   dx <- rows (vertical)   es:[di] <- start location
{SoundSetInVol}	Set the mixers volume for 8-bit mono   bl <- Volume level  bits 2-3 = mic Volume SPB, 1-3 SB 16
{SoundSetOutVol}	Set the mixers volume for 8-bit mono   bl <- Volume level  bits 0-3 = right Volume, 4-7 = left Volume
{SoundTest}	outputs a tone directly to card to see if   it will do anything at all ( no interrupts needed )
{SoundStop}	Stops a Sound Transer and Halts DMA Interrupts
ScreenDebug	Called whenever there is an error messege to print  si <- offset of error message

; Sound Blaster Pro I/O port definition
SBP_Port        dw 0220h      ; 220 - 22F Default
SBP_INT         db 0Dh        ; INT 5h Default
SBP_INTMask     db 00100000b
SBP_INTInst     db 0          ; zero = not installed
SBP_DMA         db 5h
SBP_oldV        dd ?          ; saved interrupt vector
SBP_Rate        dw SPB_DEFAULT_SAMPLE_RATE
SBP_PICOffMask  db ?          ; PIC mask to restore when exiting
SBP_PICOnMask   db ?          ; PIC mask to turn on Interrupt

; DMA register locations
DMA_Table   DMA_Type  {87h,   0h,   1h},     ; DMA 0
                      {83h,   2h,   3h},     ; DMA 1
                      {81h,   4h,   5h},     ; DMA 2
                      {82h,   6h,   7h},     ; DMA 3
                      {8Fh, 0C0h, 0C2h},     ; DMA 4
                      {8Bh, 0C4h, 0C6h},     ; DMA 5
                      {89h, 0C8h, 0CAh},     ; DMA 6
                      {8Ah, 0CCh, 0CEh}      ; DMA 7

; Sound Buffer Tracking Vars
ReadAddr        dw ?              ; Offset for soundBuff
WriteAddr       dw ?              ; Offset for soundBuff
BufDataLength   dw ?              ; amount of new data in buffer
BufMode         db 0              ; 0 - none, 1 - Play, 2 - Rec

SBP_BufOffsetTP dw ?              ; top half of offset
SBP_BufOffsetBT dw ?              ; bottom half of offset
SBP_BufLen      dw ?              ; length of sound card buffer
SBP_DMAPage     db ?
SBP_DMAOffset   dw ?
SBP_Side        db 0              ; SBP is read/writing to 0 = top, 1 = bottom
SBP_SingleLen   dw ?              ; lenght of last single cycle xfer

; Wave file vars
WavRIFFstring   db 'RIFF'
WavFMTstring    db 'WAVEfmt '
WavDATAString   db 'data'
WavHeader       WavHdrStruct < >
WavOldRate      dw ?        ; old sampling rate
WavLengthLeft   dd ?

; File buffer vars
fileMode        db ?            ; WAV, NONE
fileBuffer      db 1024 dup (?) ;1024 dup (?)
fileHandle      dw ?

; Messages mostly errors                        ;
WriteTimeOutE_Msg db '00 ER: SB Write Timeout ','$'         ; write timeout {SBP_WaitWrite}
ReadTimeOutE_Msg  db '01 ER: SB Read Timeout','$'           ;SB Card Read Timeout {SBP_WaitRead}','$'
DPS_ResetE_Msg    db '02 ER: SB DSP not Reset ','$'
BufWOFlowE_Msg    db '03 ER: SB Write Buf OF', '$'          ; write buffer overflow
BufROFlowE_Msg    db '04 ER: SB Read Buffer OF',  '$'       ; read buffer overflow
SBP_IRQE_Msg      db '05 ER: SB IRQ Not Detected', '$'
SBP_DMAE_Msg      db '06 ER: SB DMA Not Detected', '$'
SBP_WavE_Msg      db '07 ER: WAV  Not Readable',  '$'
SBP_WavFileE_Msg  db '08 ER: {WAV} File in use',  '$'

; Sound Buffer for double buffered SBP data
SoundBuf          db 55000 dup (?)    ; sound buffer number 2