From: John Tsiombikas <nuclear@member.fsf.org>
Date: Wed, 23 Jan 2019 01:00:11 +0000 (+0200)
Subject: fixed DMA bug
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dos_sbtest;a=commitdiff_plain;h=b4ee0075a2a231ef06e333b77510187aeb22f8fa

fixed DMA bug
---

diff --git a/src/au_sb.c b/src/au_sb.c
index c49b2cf..d733f20 100644
--- a/src/au_sb.c
+++ b/src/au_sb.c
@@ -89,9 +89,11 @@ static int xfer_mode;
 
 static int isplaying;
 static int cur_bits, cur_mode;
+static int curblk;
 
 static void (INTERRUPT *prev_intr_handler)();
 
+
 int sb_detect(void)
 {
 	int i;
@@ -178,11 +180,11 @@ void sb_set_output_rate(int rate)
 
 void *sb_buffer(int *size)
 {
-	*size = 65536;
-	return buffer;
+	*size = 32768;
+	return (char*)buffer + curblk * 32768;
 }
 
-void sb_start(int rate, int nchan)
+void sb_start(int rate, int bits, int nchan)
 {
 	uint16_t seg, pmsel;
 	uint32_t addr;
@@ -205,21 +207,23 @@ void sb_start(int rate, int nchan)
 		addr = (uint32_t)buffer;
 	}
 
-	if(!(size = audio_callback(buffer, 65536))) {
+	if(!(size = audio_callback(buffer, 32768))) {
 		return;
 	}
+	curblk = 1;
 
 	_disable();
 	if(!prev_intr_handler) {
 		prev_intr_handler = _dos_getvect(IRQ_TO_INTR(irq));
 	}
+	printf("setting interrupt vector: %d\n", IRQ_TO_INTR(irq));
 	_dos_setvect(IRQ_TO_INTR(irq), intr_handler);
 	_enable();
 
 	unmask_irq(irq);
 
-	cur_bits = 8;
-	cur_mode = 0;
+	cur_bits = bits;
+	cur_mode = 0;	/* TODO */
 	if(nchan > 1) {
 		cur_mode |= DSP4_MODE_STEREO;
 	}
@@ -236,6 +240,8 @@ 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;*/
+
 	/* program the DSP to start the DMA transfer */
 	write_dsp(cmd);
 	write_dsp(mode);
@@ -290,12 +296,15 @@ void sb_volume(int vol)
 static void INTERRUPT intr_handler()
 {
 	int size;
+	void *bptr = (unsigned char*)buffer + curblk * 32768;
+
+	curblk = (curblk + 1) & 1;
 
 	/* ask for more data */
-	if(!(size = audio_callback(buffer, 65536))) {
+	if(!(size = audio_callback(bptr, 32768))) {
 		sb_stop();
 	} else {
-		dma_out(dma_chan, (uint32_t)buffer, size, DMA_SINGLE);
+		dma_out(dma_chan, (uint32_t)bptr, size, DMA_SINGLE);
 		start_dsp4(cur_bits, cur_mode, size);
 	}
 
diff --git a/src/au_sb.h b/src/au_sb.h
index 0981ba6..4766b44 100644
--- a/src/au_sb.h
+++ b/src/au_sb.h
@@ -15,7 +15,7 @@ void *sb_buffer(int *size);
 
 void sb_set_output_rate(int rate);
 
-void sb_start(int rate, int nchan);
+void sb_start(int rate, int bits, int nchan);
 void sb_pause(void);
 void sb_continue(void);
 void sb_stop(void);
diff --git a/src/audio.c b/src/audio.c
index adb8e3e..88b8400 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -4,7 +4,7 @@
 
 struct audrv {
 	void *(*get_buffer)(int *size);
-	void (*start)(int rate, int nchan);
+	void (*start)(int rate, int bits, int nchan);
 	void (*pause)(void);
 	void (*cont)(void);
 	void (*stop)(void);
@@ -47,9 +47,9 @@ int audio_callback(void *buf, int sz)
 	return cbfunc(buf, sz, cbcls);
 }
 
-void audio_play(int rate, int nchan)
+void audio_play(int rate, int bits, int nchan)
 {
-	drv.start(rate, nchan);
+	drv.start(rate, bits, nchan);
 }
 
 void audio_pause(void)
diff --git a/src/audio.h b/src/audio.h
index 1fde706..c522134 100644
--- a/src/audio.h
+++ b/src/audio.h
@@ -1,20 +1,3 @@
-/*
-pcboot - bootable PC demo/game kernel
-Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY, without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <https://www.gnu.org/licenses/>.
-*/
 #ifndef AUDIO_H_
 #define AUDIO_H_
 
@@ -25,7 +8,7 @@ void audio_init(void);
 void audio_set_callback(audio_callback_func func, void *cls);
 int audio_callback(void *buf, int sz);
 
-void audio_play(int rate, int nchan);
+void audio_play(int rate, int bits, int nchan);
 void audio_pause(void);
 void audio_resume(void);
 void audio_stop(void);
diff --git a/src/dma.c b/src/dma.c
index 92f0a1b..17baead 100644
--- a/src/dma.c
+++ b/src/dma.c
@@ -100,8 +100,8 @@ static void dma_io(int chan, uint32_t phyaddr, int size, unsigned int flags, uns
 	mask(chan);
 	outp(DMA_CLR_FLIPFLOP(chan), 0);
 
-	/* single / block / cascade */
-	mode = ((flags & 3) << 6) | MODE_CHAN(chan);
+	/* first 2 bits of flags correspond to the mode bits 6,7 */
+	mode = ((flags & 3) << 6) | dir | MODE_CHAN(chan);
 	if(flags & DMA_DECR) mode |= MODE_DECR;
 	if(flags & DMA_AUTO) mode |= MODE_AUTO;
 	outp(DMA_MODE(chan), mode);
diff --git a/src/main.c b/src/main.c
index 264c04e..1d148d0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -43,7 +43,7 @@ int main(int argc, char **argv)
 				if(audio_isplaying()) {
 					audio_stop();
 				} else {
-					audio_play(22050, 1);
+					audio_play(22050, 8, 1);
 				}
 				break;
 			default: