DOSSEG .MODEL SMALL .STACK 200h .CODE .386 ASSUME CS:@CODE, DS:@CODE Ideal 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 OldInt dd 0 ;for the old DMA interrupt BaseAddress dw 220h IrqNumber db 7 DMANumber db 1 SampleSeg dw 0 SampleOff dw 0 FileName db "jamhot.sam",0 SamLength dw ? STRUC DMAInfo Page dw ?,? Length dw ?,? Offset dw ?,? Next dw 0,0 ;changes 2nd one to a "2" if 2 buffers are needed Current dw 0 ;0 or 1 ENDS DMAInfo DMA DMAInfo <> 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 ;================== ;==- Interrupts -== ;================== PROC DMAINT FAR pusha cli mov dx,[cs:BaseAddress] add dx,0eh in al,dx ;acknowledge interrupt xor [cs:DMA.Current],1 mov bx,[cs:DMA.Current] add bx,bx mov bx,[cs:bx + DMA.NEXT] mov ax,[cs:bx + DMA.Page] mov ah,al mov cx,[cs:bx + DMA.Length] mov dx,[cs:bx + DMA.Offset] call TransferDma mov al,20h out 20h,al ;end of hardware interrupt popa sti iret ENDP DMAINT ;====================== ;==- Start Transfer -== ;====================== PROC StartTransferDma NEAR pusha mov al,[cs:IrqNumber] add al,8 cbw shl al,2 mov bx,ax push es sub ax,ax mov es,ax mov ax,[es:bx] mov [WORD LOW cs:OldInt],ax ; Grab the current interrupt mov ax,[es:bx+2] mov [WORD HIGH cs:OldInt],ax ; so we can restore it later pop es mov ax,[cs:DMA.Page] mov ah,al mov cx,[cs:DMA.Length] mov dx,[cs:DMA.Offset] mov al,5 out 0ah,al ;Mask off channel 1 xor al,al out 0ch,al ;Clear byte pointer F/F to lowerbyte mov al,49h out 0bh,al ;Set transfer mode to DAC (ADC = 45h) mov al,dl ;LSB of BASE_ADDRESS out 2,al mov al,dh ;MSB of BASE_ADDRESS out 2,al mov al,ah out 83h,al ;Page Number mov al,cl out 3,al ;LSB of DATA_Length mov al,ch out 3,al ;MSB of DATA_Length mov al,1 out 0ah,al ;Enable Channel 1 mov ax,offset DMAInt call DoRealInt mov al,14h ;function 14h DMAmode 8-bit DAC call Sendcommand mov al,cl ;send LSB of DATALENGTH call SendCommand mov al,ch ;send MSB of DATALENGTH call SendCommand popa ret ENDP StartTransferDma ;ah= page number ;dx= BASE_ADDRESS ;cx= DATA_LENGTH (-1) PROC TransferDma NEAR pusha mov al,5 out 0ah,al ;Mask off channel 1 xor al,al out 0ch,al ;Clear byte pointer F/F to lowerbyte mov al,49h out 0bh,al ;Set transfer mode to DAC (ADC = 45h) mov al,dl ;LSB of BASE_ADDRESS out 2,al mov al,dh ;MSB of BASE_ADDRESS out 2,al mov al,ah out 83h,al ;Page Number mov al,cl out 3,al ;LSB of DATA_Length mov al,ch out 3,al ;MSB of DATA_Length mov al,1 out 0ah,al ;Enable Channel 1 mov al,14h ;function 14h DMAmode 8-bit DAC call Sendcommand mov al,cl ;send LSB of DATALENGTH call SendCommand mov al,ch ;send MSB of DATALENGTH call SendCommand popa ret ENDP TransferDMA ;ah= TC (Time Constant = 256 - 1,000,000/HZ) PROC SetTimeConstant NEAR mov al,40h call SendCommand mov al,ah call SendCommand ret ENDP SetTimeConstant PROC TurnOffSpeaker NEAR mov al,0d3h ;turn off speaker call Sendcommand ret ENDP TurnOffSpeaker PROC HaltDMA NEAR mov al,0d0h ;Halt DMA call SendCommand ret ENDP HaltDma ;al = command PROC SendCommand NEAR push dx push ax mov dx,[cs:BaseAddress] add dx,0ch @@Sendcommandloop: in al,dx or al,al js @@Sendcommandloop pop ax out dx,al pop dx ret ENDP SendCommand PROC TurnOnSpeaker NEAR mov al,0d1h call SendCommand ret ENDP TurnOnSpeaker ;input- none ;output al=0 successful ; al=1 unsuccessful ;DESTROYED: ax,dx,cx PROC DspReset NEAR mov dx,[cs:baseaddress] add dx,06h mov al,1 out dx,al mov cx,1000 push di rep lodsb ;wait for at least 3�S pop di xor al,al out dx,al add dx,8 ;check WhichBuffer (22eh) mov cx,12000 waitforstat: in al,dx dec cx je errorstat test al,10000000b jz waitforstat mov cx,10000 sub dx,4 ;(22ah) waitforstat2: in al,dx dec cx je errorstat cmp al,0aah jne waitforstat2 mov al,0 ret errorstat: mov al,1 ret ENDP DspReset ;======================== ;==- Start Interrupts -== ;======================== ;cs:ax=location of interrupt PROC DoRealint NEAR pushf ; Push flags push bx push cx push dx cli ; Disable interrupts mov dx,ax mov al,[cs:IrqNumber] add al,8 cbw ; Convrt byte to word shl ax,2 ; Shift w/zeros fill mov bx,ax push es sub ax,ax mov es,ax mov [es:bx],dx mov [es:bx+2],cs pop es mov cl,[cs:IrqNumber] mov ah,1 shl ah,cl ; Shift w/zeros fill not ah in al,21h ; port 21h, 8259-1 int IMR and al,ah out 21h,al ; port 21h, 8259-1 int comands pop dx pop cx pop bx popf ; Pop flags sti ret ENDP DoRealint PROC UnDoREALint NEAR pushf pusha cli mov al,[cs:IrqNumber] add al,8 cbw shl ax,2 mov di,ax push es sub ax,ax mov es,ax mov ax,[WORD LOW cs:OldInt] mov [es:di],ax mov ax,[WORD HIGH cs:OldInt] mov [es:di+2],ax pop es mov cl,[cs:IrqNumber] ; (=7) mov ah,1 shl ah,cl ; Shift w/zeros fill in al,21h ; port 21h, 8259-1 int IMR or al,ah out 21h,al ; port 21h, 8259-1 int comands popa popf ; Pop flags sti ret ENDP UnDoREALint ;Figgures the DMA buffer info PROC CalcForDMA NEAR pushad push ds mov ax,cs mov ds,ax mov es,ax mov [2 + DMA.Next],0 ;assume we do only 1 buffer movzx eax,[SampleSeg] movzx edx,[SampleOff] call MakePage cmp cx,[SamLength] ;is max less than needed? jb Skiplengthset ;yes, must do 2 buffers mov cx,[SamLength] mov [2 + DMA.NEXT],2 jmp NoMore Skiplengthset: mov bx,[SamLength] sub bx,cx dec bx mov [2 + DMA.Length],bx mov [2 + DMA.Offset],0 mov [2 + DMA.Page],ax inc [2 + DMA.Page] NoMore: mov [DMA.Page],ax mov [DMA.Offset],dx dec cx mov [DMA.Length],cx pop ds popad ret ENDP CalcForDMA ;input: eax=segment ; edx=offset ;output: ax=page ; dx=offset ; cx=MAX_LENGTH PROC MakePage NEAR shl eax,4 add edx,eax ;edx = 32bit absolute address ror edx,16 mov al,dl ;ax= page xor ah,ah ror edx,16 mov cx,dx neg cx ret ENDP MakePage ; returns -1 if load not successful PROC LoadSample NEAR pusha push ds mov ax,cs mov ds,ax mov dx,offset FileName mov ax,3D00h ;open the file int 21h jc @@Error mov bx,ax xor dx,dx ;load at offset 0 mov cx,0ffffh ;read in a whole segments worth mov ds,[cs:SampleSeg] mov ax,3F00h ; Load in the sample int 21h mov [cs:SamLength],ax mov ax,3E00h ;close the file int 21h ;now fix the sam so it's playable on a SB push es push ds pop es mov si,0 mov di,0 mov cx,[cs:SamLength] cld FixItLoop: lodsb add al,128 stosb loop FixItLoop pop es pop ds popa xor ax,ax ret @@Error: pop ds popa mov ax,-1 ret ENDP LoadSample 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 START: mov bx,ss add bx,20h ;put sample right after stack mov [cs:SampleSeg],bx call LoadSample call CalcForDMA call DspReset mov ah, 256- 1000000/8000 ; 256- 1000000/ HZ call SetTimeConstant call TurnOnSpeaker call StartTransferDMA mov ah,0 int 16h ;wait for a keypress call HaltDMA call UnDoRealInt call TurnOffSpeaker call DSPReset mov ax,4c00h int 21h END START