SDL_mintaudiointerrupt.S
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/*
* Audio interrupt routines
*
* Patrice Mandin
*/
.text
.globl _SDL_MintAudio_Callback
.globl _SDL_MintAudio_IntDma
.globl _SDL_MintAudio_IntXbios
.globl _SDL_MintAudio_IntGsxb
.globl _SDL_MintAudio_mutex
.globl _SDL_MintAudio_audiobuf
.globl _SDL_MintAudio_numbuf
.globl _SDL_MintAudio_audiosize
/*
How it works:
- Audio is playing buffer #0 (resp. #1)
- We must calculate a sample in buffer #1 (resp. #0)
so we first call the callback to do it
- Then we swap the buffers
*/
/*--- DMA 8 bits interrupt vector ---*/
.text
_SDL_MintAudio_IntDma:
/* Check if we are not already running */
tstw _SDL_MintAudio_mutex
bnes intdma_end
notw _SDL_MintAudio_mutex
/* Reenable interrupts */
movew #0x2300,sr
/* Swap buffers */
moveml d0-d1/a0-a1,sp@-
movel _SDL_MintAudio_numbuf,d0
movel _SDL_MintAudio_audiobuf,d1
eorl #1,d0
beqs intdma_buffer0
movel _SDL_MintAudio_audiobuf+4,d1
intdma_buffer0:
movel d0,_SDL_MintAudio_numbuf
/* Callback */
movel d1,sp@-
jsr _SDL_MintAudio_Callback
movel sp@+,d1
/* Modify DMA addresses */
lea 0xffff8900:w,a0
moveb d1,a0@(0x07) /* Start address */
rorl #8,d1
moveb d1,a0@(0x05)
rorl #8,d1
moveb d1,a0@(0x03)
swap d1
addl _SDL_MintAudio_audiosize,d1
moveb d1,a0@(0x13) /* End address */
rorl #8,d1
moveb d1,a0@(0x11)
rorl #8,d1
moveb d1,a0@(0x0f)
moveml sp@+,d0-d1/a0-a1
clrw _SDL_MintAudio_mutex
intdma_end:
bclr #5,0xfffffa0f:w
rte
/*--- Xbios interrupt vector ---*/
.text
_SDL_MintAudio_IntXbios:
/* Check if we are not already running */
tstw _SDL_MintAudio_mutex
bnes intxbios_end
notw _SDL_MintAudio_mutex
/* Reenable interrupts */
movew #0x2300,sr
/* Swap buffers */
moveml d0-d2/a0-a2,sp@-
movel _SDL_MintAudio_numbuf,d0
movel _SDL_MintAudio_audiobuf,a0
eorl #1,d0
beqs intxbios_buffer0
movel _SDL_MintAudio_audiobuf+4,a0
intxbios_buffer0:
movel d0,_SDL_MintAudio_numbuf
/* Callback */
moveml a0,sp@-
jsr _SDL_MintAudio_Callback
moveml sp@+,a0
/* Setbuffer xbios function */
movel _SDL_MintAudio_audiosize,d1
lea a0@(0,d1:l),a1
movel a1,sp@-
movel a0,sp@-
clrw sp@-
movew #131,sp@-
trap #14
lea sp@(12),sp
moveml sp@+,d0-d2/a0-a2
clrw _SDL_MintAudio_mutex
intxbios_end:
bclr #5,0xfffffa0f:w
rte
/*--- GSXB interrupt vector ---*/
.text
_SDL_MintAudio_IntGsxb:
/* Check if we are not already running */
tstw _SDL_MintAudio_mutex
bnes intgsxb_end
notw _SDL_MintAudio_mutex
/* Swap buffers */
moveml d0-d2/a0-a2,sp@-
movel _SDL_MintAudio_numbuf,d0
movel _SDL_MintAudio_audiobuf,a0
eorl #1,d0
beqs intgsxb_buffer0
movel _SDL_MintAudio_audiobuf+4,a0
intgsxb_buffer0:
movel d0,_SDL_MintAudio_numbuf
/* Callback */
moveml a0,sp@-
jsr _SDL_MintAudio_Callback
moveml sp@+,a0
/* Setbuffer xbios function */
movel _SDL_MintAudio_audiosize,d1
lea a0@(0,d1:l),a1
movel a1,sp@-
movel a0,sp@-
clrw sp@-
movew #131,sp@-
trap #14
lea sp@(12),sp
moveml sp@+,d0-d2/a0-a2
clrw _SDL_MintAudio_mutex
intgsxb_end:
rts
/*--- Common variables ---*/
.data
.even
.comm _SDL_MintAudio_mutex,4
.even
.comm _SDL_MintAudio_audiobuf,8
.even
.comm _SDL_MintAudio_numbuf,4
.even
.comm _SDL_MintAudio_audiosize,4