Category : Music and Digitized Voice
Archive   : SBF3.ZIP
Filename : SBP_CHK.ASM

; Reset routine for Soundblaster
; Coded for the SBF by millerje
; Modified (to replace sbp.asm) by cmb.

DSP_RESET equ 6
DSP_DATA_AVAIL equ 0Eh
DSP_READ_DATA equ 0Ah

.MODEL large,C

.DATA
PUBLIC SbIOaddr, SbIRQ, SbDMAchan, SbType

SbIOaddr dw 220h
SbIRQ dw 7
SbDMAchan dw 1
SbType dw 2

.CODE
PUBLIC Sb_Init
Sb_Init PROC

; Reset the DSP by sending 1, (delay), then 0
mov al,1
mov dx,[SbIOaddr]
add dx,DSP_RESET
out dx,al

; Do a wait for I/O (each bus access takes 1 microsecond on a standard ISA)
; Must be at least 3.3 microseconds
in al,dx
in al,dx
in al,dx
in al,dx

mov al,0
mov dx,[SbIOaddr]
add dx,DSP_RESET
out dx,al

mov cx,64h
DataWait:
mov dx,[SbIOaddr]
add dx,DSP_DATA_AVAIL
in al,dx
test al,80h
jnz YesData ;a byte is waiting...
loop DataWait

; Timed out- there's no data there
jmp short exit

; Data is waiting, if = 0AAh, there's a SB here!
YesData:
mov dx,[SbIOaddr]
add dx,DSP_READ_DATA
in al,dx
cmp al,0AAh
je YepSB ;Found the ID byte
loop DataWait ;No, wait for next byte

; timed out- can't find signature
jmp short exit

YepSB:
mov ax,0
ret

exit:
mov ax,1
ret

Sb_Init ENDP

END