X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dos_auplay;a=blobdiff_plain;f=src%2Fau_sb.c;h=0daa7c0d57d12171dc9c474af8f7dbd5a5e8fcc4;hp=d733f20b71bc910403ba4d0396adb035e69f1fbe;hb=49ef4e243def029b7e68bf92141acbeac600e1e8;hpb=87ef5613bb9baae3903237321c15133066139f7c

diff --git a/src/au_sb.c b/src/au_sb.c
index d733f20..0daa7c0 100644
--- a/src/au_sb.c
+++ b/src/au_sb.c
@@ -9,6 +9,8 @@
 #include "dma.h"
 #include "intr.h"
 
+#define BUFSIZE			16384
+
 #define REG_MIXPORT		(base_port + 0x4)
 #define REG_MIXDATA		(base_port + 0x5)
 #define REG_RESET		(base_port + 0x6)
@@ -84,12 +86,12 @@ static const char *sbname(int ver);
 static int base_port;
 static int irq, dma_chan, dma16_chan, dsp_ver;
 static int dsp4;
-static void *buffer;
-static int xfer_mode;
 
-static int isplaying;
-static int cur_bits, cur_mode;
-static int curblk;
+static void *buffer[2];
+static volatile int wrbuf;
+
+static volatile int isplaying;
+static int cur_bits, cur_mode, auto_init;
 
 static void (INTERRUPT *prev_intr_handler)();
 
@@ -180,19 +182,19 @@ void sb_set_output_rate(int rate)
 
 void *sb_buffer(int *size)
 {
-	*size = 32768;
-	return (char*)buffer + curblk * 32768;
+	*size = BUFSIZE / 2;
+	return buffer[wrbuf];
 }
 
 void sb_start(int rate, int bits, int nchan)
 {
 	uint16_t seg, pmsel;
-	uint32_t addr;
-	int size;
+	uint32_t addr, next64k;
+	int size, num_samples;
 
-	if(!buffer) {
-		/* allocate a 64k-aligned 64k buffer in low memory */
-		if(!(seg = dpmi_alloc(65536 * 2 / 16, &pmsel))) {
+	if(!buffer[1]) {
+		/* allocate a buffer in low memory that doesn't cross 64k boundaries */
+		if(!(seg = dpmi_alloc(BUFSIZE * 2 / 16, &pmsel))) {
 			fprintf(stderr, "sb_start: failed to allocate DMA buffer\n");
 			return;
 		}
@@ -200,17 +202,34 @@ void sb_start(int rate, int bits, int nchan)
 		printf("DBG allocated seg: %x, addr: %lx\n", (unsigned int)seg,
 				(unsigned long)seg << 4);
 
-		addr = ((uint32_t)(seg << 4) + 0xffff) & 0xffff0000;
-		printf("DBG aligned: %lx\n", (unsigned long)addr);
-		buffer = (void*)addr;
-	} else {
-		addr = (uint32_t)buffer;
+		addr = (uint32_t)seg << 4;
+		next64k = (addr + 0x10000) & 0xffff0000;
+		if(next64k - addr < BUFSIZE) {
+			addr = next64k;
+		}
+
+		printf("DBG aligned: %lx (mid: %lx)\n", (unsigned long)addr, (unsigned long)(addr + BUFSIZE / 2));
+		buffer[0] = (void*)addr;
+		buffer[1] = (void*)(addr + BUFSIZE / 2);
+		wrbuf = 0;
 	}
 
-	if(!(size = audio_callback(buffer, 32768))) {
+	/* Auto-init playback mode:
+	 * fill the whole buffer with data, program the DMA for BUFSIZE transfer,
+	 * and program the DSP for BUFSIZE/2 transfer. We'll get an interrupt in the
+	 * middle, while the DSP uses the upper half, and we'll refill the bottom half.
+	 * Then continue ping-ponging the two halves of the buffer until we run out of
+	 * data.
+	 */
+	auto_init = 1;
+
+	/* TODO: if size <= BUFSIZE, do a single transfer instead */
+	wrbuf = 0;
+	if(!(size = audio_callback(buffer[wrbuf], BUFSIZE))) {
 		return;
 	}
-	curblk = 1;
+	addr = (uint32_t)buffer[wrbuf];
+	num_samples = bits == 8 ? size : size / 2;
 
 	_disable();
 	if(!prev_intr_handler) {
@@ -223,24 +242,22 @@ void sb_start(int rate, int bits, int nchan)
 	unmask_irq(irq);
 
 	cur_bits = bits;
-	cur_mode = 0;	/* TODO */
+	cur_mode = bits == 8 ? 0 : DSP4_MODE_SIGNED;
 	if(nchan > 1) {
 		cur_mode |= DSP4_MODE_STEREO;
 	}
 
 	write_dsp(DSP_ENABLE_OUTPUT);
-	dma_out(dma_chan, addr, size, DMA_SINGLE);
+	dma_out(cur_bits == 8 ? dma_chan : dma16_chan, addr, BUFSIZE, DMA_SINGLE | DMA_AUTO);
 	sb_set_output_rate(rate);
-	start_dsp4(cur_bits, cur_mode, size);
+	start_dsp4(cur_bits, cur_mode, num_samples / 2);
 	isplaying = 1;
 }
 
 static void start_dsp4(int bits, unsigned int mode, int num_samples)
 {
 	unsigned char cmd = bits == 8 ? DSP4_START_DMA8 : DSP4_START_DMA16;
-	assert(bits == 8 || bits == 16);
-
-	/*cmd |= DSP4_AUTO | DSP4_FIFO;*/
+	cmd |= DSP4_AUTO | DSP4_FIFO;
 
 	/* program the DSP to start the DMA transfer */
 	write_dsp(cmd);
@@ -276,10 +293,7 @@ void sb_stop(void)
 	_dos_setvect(IRQ_TO_INTR(irq), prev_intr_handler);
 	_enable();
 
-	/* no need to stop anything if we're in single-cycle mode */
-	if(cur_mode & DSP4_AUTO) {
-		write_dsp(cur_bits == 8 ? DSP_END_DMA8 : DSP_END_DMA16);
-	}
+	write_dsp(cur_bits == 8 ? DSP_END_DMA8 : DSP_END_DMA16);
 	isplaying = 0;
 }
 
@@ -296,20 +310,29 @@ void sb_volume(int vol)
 static void INTERRUPT intr_handler()
 {
 	int size;
-	void *bptr = (unsigned char*)buffer + curblk * 32768;
+	void *bptr = buffer[wrbuf];
+	uint32_t addr = (uint32_t)bptr;
 
-	curblk = (curblk + 1) & 1;
+	wrbuf ^= 1;
 
 	/* ask for more data */
-	if(!(size = audio_callback(bptr, 32768))) {
+	if(!(size = audio_callback(bptr, BUFSIZE / 2))) {
 		sb_stop();
-	} else {
-		dma_out(dma_chan, (uint32_t)bptr, size, DMA_SINGLE);
-		start_dsp4(cur_bits, cur_mode, size);
 	}
 
 	/* acknowledge the interrupt */
-	inp(REG_INTACK);
+	if(cur_bits == 8) {
+		inp(REG_INTACK);
+	} else {
+		/*
+		unsigned char istat;
+		outp(REG_MIXPORT, 0x82);
+		istat = inp(REG_MIXDATA);
+		if(istat & 2) {
+		*/
+			inp(REG_INT16ACK);
+		//}
+	}
 
 	if(irq > 7) {
 		outp(PIC2_CMD, OCW2_EOI);