Added Uxn-based synth

build.sh

@@ -6,6 +6,7 @@ clang-format -i src/uxn.h
 clang-format -i src/uxn.c
 clang-format -i src/emulator.c
 clang-format -i src/debugger.c
+clang-format -i src/apu.c
 
 echo "Cleaning.."
 rm -f ./bin/assembler
@@ -19,12 +20,12 @@ if [ "${1}" = '--debug' ];
 then
 	echo "[debug]"
     cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined src/assembler.c -o bin/assembler
-	cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined src/uxn.c src/emulator.c -L/usr/local/lib -lSDL2 -o bin/emulator
+	cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined src/uxn.c src/emulator.c src/apu.c -L/usr/local/lib -lSDL2 -o bin/emulator
     cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined src/uxn.c src/debugger.c -o bin/debugger
 else
 	cc src/assembler.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o bin/assembler
 	cc src/uxn.c src/debugger.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o bin/debugger
-	cc src/uxn.c src/emulator.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -L/usr/local/lib -lSDL2 -o bin/emulator
+	cc src/uxn.c src/emulator.c src/apu.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -L/usr/local/lib -lSDL2 -o bin/emulator
 fi
 
 echo "Assembling.."

projects/examples/blank.usm

@@ -11,7 +11,7 @@
 |0140 ;Keys { key 1 }
 |0150 ;Mouse { x 2 y 2 state 1 chord 1 }
 |0160 ;File { pad 8 name 2 length 2 load 2 save 2 }
-|0170 ;Audio { ch1asdr 2 ch2asdr 2 ch3asdr 2 ch4asdr 2 ch1pitch 1 ch1vol 1 ch2pitch 1 ch2vol 1 ch3pitch 1 ch3vol 1 ch4pitch 1 ch4vol 1 }
+|0180 ;Audio { wave 2 envelope 2 pad 4 volume 1 pitch 1 play 1 value 2 delay 2 finish 1 }
 |01F0 ;System { pad 8 r 2 g 2 b 2 }
 
 ( vectors )

projects/examples/dev.audio.usm

@@ -6,6 +6,9 @@
 %++  { #0001 ADD2 }
 %MOD { DUP2 DIV MUL SUB }
 %TRACK { ,track.ch1 #00 ~track.active #0020 MUL2 ADD2 }
+%SOUND { STH #00 =Audio.value STHr #00 =Audio.delay }
+%SOUND2 { =Audio.value =Audio.delay }
+%SOUND_FINISH { #00 =Audio.finish }
 
 ( variables )
 
@@ -19,6 +22,8 @@
 ;knob { x 2 y 2 value 1 }
 ;head { pos 1 }
 ;track { active 1 ch1 20 ch2 20 ch3 20 ch4 20 }
+;adsr { ch1a 1 ch1d 1 ch1s 1 ch1r 1 ch2a 1 ch2d 1 ch2s 1 ch2r 1 ch3a 1 ch3d 1 ch3s 1 ch3r 1 ch4a 1 ch4d 1 ch4s 1 ch4r 1 }
+;volume { ch1 1 ch2 1 ch3 1 ch4 1 }
 
 ( devices )
 
@@ -30,7 +35,7 @@
 |0150 ;Keys { key 1 }
 |0160 ;Mouse  { vector 2 x 2 y 2 state 1 chord 1 }
 |0170 ;File { pad 8 name 2 length 2 load 2 save 2 }
-|0180 ;Audio { ch1adsr 2 ch2adsr 2 ch3adsr 2 ch4adsr 2 ch1vol 1 ch1pitch 1 ch2vol 1 ch2pitch 1 ch3vol 1 ch3pitch 1 ch4vol 1 ch4pitch 1 }
+|0180 ;Audio { wave 2 envelope 2 pad 4 volume 1 pitch 1 play 1 value 2 delay 2 finish 1 }
 
 ( vectors )
 
@@ -51,9 +56,10 @@
 	~trkframe.x2 =ctlframe.x2 ~chnframe.y2 =ctlframe.y2
 
 	( default settings )
-	#048c =Audio.ch1adsr #88 =Audio.ch1vol
+	,adsr-envelope =Audio.envelope
-	#159d =Audio.ch2adsr #88 =Audio.ch2vol
+	#00 =adsr.ch1a #40 =adsr.ch1d #80 =adsr.ch1s #c0 =adsr.ch1r #88 =volume.ch1
-	#26ae =Audio.ch3adsr #88 =Audio.ch3vol
+	#10 =adsr.ch2a #50 =adsr.ch2d #90 =adsr.ch2s #d0 =adsr.ch2r #88 =volume.ch2
+	#20 =adsr.ch3a #60 =adsr.ch3d #a0 =adsr.ch3s #e0 =adsr.ch3r #88 =volume.ch3
 
 	,draw-timeline JSR2
 	,draw-controls JSR2
@@ -110,29 +116,29 @@ BRK
 	
 	~Mouse.x ~ctlframe.x1 SUB2 8- 8/ SWP POP #02 DIV
 	DUP #00 NEQ ^$no-a JNZ
-		,Audio #00 ~track.active #02 MUL ADD2 PEK2
+		,adsr #00 ~track.active #04 MUL ADD2 PEK2
 		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD
-		,Audio #00 ~track.active #02 MUL ADD2 POK2 $no-a
+		,adsr #00 ~track.active #04 MUL ADD2 POK2 $no-a
 	DUP #01 NEQ ^$no-d JNZ
-		,Audio #00 ~track.active #02 MUL ADD2 PEK2
+		,adsr #00 ~track.active #04 MUL ADD2 #0001 ADD2 PEK2
-		DUP #f0 AND STH #01 ~Mouse.state #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD
-		,Audio #00 ~track.active #02 MUL ADD2 POK2 $no-d
+		,adsr #00 ~track.active #04 MUL ADD2 #0001 ADD2 POK2 $no-d
 	DUP #02 NEQ ^$no-s JNZ
-		,Audio #00 ~track.active #02 MUL ADD2 ++ PEK2
+		,adsr #00 ~track.active #04 MUL ADD2 #0002 ADD2 PEK2
 		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD
-		,Audio #00 ~track.active #02 MUL ADD2 ++ POK2 $no-s
+		,adsr #00 ~track.active #04 MUL ADD2 #0002 ADD2 POK2 $no-s
 	DUP #03 NEQ ^$no-r JNZ
-		,Audio #00 ~track.active #02 MUL ADD2 ++ PEK2
+		,adsr #00 ~track.active #04 MUL ADD2 #0003 ADD2 PEK2
-		DUP #f0 AND STH #01 ~Mouse.state #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
-		,Audio #00 ~track.active #02 MUL ADD2 ++ POK2 $no-r
-	DUP #05 NEQ ^$no-left JNZ
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 PEK2
 		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 POK2 $no-left
+		,adsr #00 ~track.active #04 MUL ADD2 #0003 ADD2 POK2 $no-r
+	DUP #05 NEQ ^$no-left JNZ
+		,volume #00 ~track.active ADD2 PEK2
+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD
+		,volume #00 ~track.active ADD2 POK2 $no-left
 	DUP #06 NEQ ^$no-right JNZ
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 PEK2
+		,volume #00 ~track.active ADD2 PEK2
 		DUP #f0 AND STH #01 ~Mouse.state #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 POK2 $no-right
+		,volume #00 ~track.active ADD2 POK2 $no-right
 	POP
 	( release ) #00 =Mouse.state
 	,draw-controls JSR2
@@ -146,21 +152,30 @@ BRK
 	DUP #ff NEQ ^$skip1 JNZ
 		POP ^$listen2 JMP
 	$skip1
-	#00 SWP ,notes ADD2 PEK2 =Audio.ch1pitch
+	#00 SWP ,notes ADD2 PEK2 =Audio.pitch
+	~volume.ch1 =Audio.volume
+	,square-wave =Audio.wave
+	#00 =Audio.play
 	$listen2
 	,track.ch2 #00 ~head.pos #08 DIV ADD2 PEK2 
 	#01 SUB
 	DUP #ff NEQ ^$skip2 JNZ
 		POP ^$listen3 JMP
 	$skip2
-	#00 SWP ,notes ADD2 PEK2 =Audio.ch2pitch
+	#00 SWP ,notes ADD2 PEK2 =Audio.pitch
+	~volume.ch2 =Audio.volume
+	,square-wave =Audio.wave
+	#01 =Audio.play
 	$listen3
 	,track.ch3 #00 ~head.pos #08 DIV ADD2 PEK2 
 	#01 SUB
 	DUP #ff NEQ ^$skip3 JNZ
 		POP ^$end JMP
 	$skip3
-	#00 SWP ,notes ADD2 PEK2 =Audio.ch3pitch
+	#00 SWP ,notes ADD2 PEK2 =Audio.pitch
+	~volume.ch3 =Audio.volume
+	,triangle-wave =Audio.wave
+	#02 =Audio.play
 	$end
 
 RTN
@@ -264,18 +279,18 @@ RTN
 	~trkframe.x1 #0018 SUB2 DUP2 ~trkframe.y1 ,draw-octave JSR2
 	~trkframe.y1 #0038 ADD2 ,draw-octave JSR2
 	~trkframe.x1 #0028 SUB2 =Sprite.x
-	~trkframe.y1 =Sprite.y
+	~trkframe.y1 #0030 ADD2 =Sprite.y
-	,font_hex #0060 ADD2 =Sprite.addr
+	,font_hex #0028 ADD2 =Sprite.addr
 	#03 =Sprite.color 
 	~trkframe.x1 #0030 SUB2 =Sprite.x
-	,font_hex #0020 ADD2 =Sprite.addr
+	,font_hex #0060 ADD2 =Sprite.addr
 	#03 =Sprite.color 
 	~trkframe.x1 #0028 SUB2 =Sprite.x
-	~trkframe.y1 #0038 ADD2 =Sprite.y
+	~trkframe.y1 #0068 ADD2 =Sprite.y
-	,font_hex #0060 ADD2 =Sprite.addr
+	,font_hex #0020 ADD2 =Sprite.addr
 	#03 =Sprite.color 
 	~trkframe.x1 #0030 SUB2 =Sprite.x
-	,font_hex #0018 ADD2 =Sprite.addr
+	,font_hex #0060 ADD2 =Sprite.addr
 	#03 =Sprite.color 
 
 RTN
@@ -312,24 +327,24 @@ RTN
 	( env )
 	~ctlframe.x1 8+ ~ctlframe.y1 8+ #02 ,env_txt ,draw-label JSR2
 	~ctlframe.x1 8+ ~ctlframe.y1 #0010 ADD2 
-		,Audio #00 ~track.active #02 MUL ADD2 PEK2 #04 SFT
+		,adsr #00 ~track.active #04 MUL ADD2 PEK2 #04 SFT
 		,draw-knob JSR2
 	~ctlframe.x1 #0018 ADD2 ~ctlframe.y1 #0010 ADD2
-		,Audio #00 ~track.active #02 MUL ADD2 PEK2 #0f AND
+		,adsr #00 ~track.active #04 MUL ADD2 #0001 ADD2 PEK2 #04 SFT
 		,draw-knob JSR2
 	~ctlframe.x1 #0028 ADD2 ~ctlframe.y1 #0010 ADD2
-		,Audio #00 ~track.active #02 MUL ADD2 ++ PEK2 #04 SFT
+		,adsr #00 ~track.active #04 MUL ADD2 #0002 ADD2 PEK2 #04 SFT
 		,draw-knob JSR2
 	~ctlframe.x1 #0038 ADD2 ~ctlframe.y1 #0010 ADD2 
-		,Audio #00 ~track.active #02 MUL ADD2 ++ PEK2 #0f AND
+		,adsr #00 ~track.active #04 MUL ADD2 #0003 ADD2 PEK2 #04 SFT
 		,draw-knob JSR2
 	( vol )
 	~ctlframe.x1 #0058 ADD2 ~ctlframe.y1 8+ #02 ,vol_txt ,draw-label JSR2
 	~ctlframe.x1 #0058 ADD2 ~ctlframe.y1 #0010 ADD2
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 PEK2 #04 SFT
+		,volume #00 ~track.active ADD2 PEK2 #04 SFT
 	,draw-knob JSR2
 	~ctlframe.x1 #0068 ADD2 ~ctlframe.y1 #0010 ADD2 
-		,Audio 8+ #00 ~track.active #02 MUL ADD2 PEK2 #0f AND
+		,volume #00 ~track.active ADD2 PEK2 #0f AND
 	,draw-knob JSR2
 
 RTN
@@ -415,6 +430,27 @@ RTN
 
 RTN
 
+@adsr-envelope ( -- )
+	#7f ,adsr #00 ~Audio.play #04 MUL ADD2 PEK2 SOUND
+	#40 ,adsr #00 ~Audio.play #04 MUL ADD2 #0001 ADD2 PEK2 SOUND
+	#40 ,adsr #00 ~Audio.play #04 MUL ADD2 #0002 ADD2 PEK2 SOUND
+	#00 ,adsr #00 ~Audio.play #04 MUL ADD2 #0003 ADD2 PEK2 SOUND
+	SOUND_FINISH
+	BRK
+
+@square-wave ( -- )
+	#5800 SOUND
+	#5880 SOUND
+	#a800 SOUND
+	#a880 SOUND
+	BRK
+
+@triangle-wave ( -- )
+	#7f40 SOUND
+	#8180 SOUND
+	#0040 SOUND
+	BRK
+
 @ch1_txt [ CHN0 00 ]
 @ch2_txt [ CHN1 00 ]
 @ch3_txt [ CHN2 00 ]
@@ -458,13 +494,13 @@ RTN
 ]
 
 @knob_offsetx [
-	04 05 06 07 08 07 06 05 
+	01 00 00 00 00 01 02 03
-	04 04 03 02 01 00 01 02
+	05 06 07 08 08 08 08 07
 ]
 
 @knob_offsety [
-	00 01 02 03 04 05 06 07 
+	07 06 05 03 02 01 00 00
-	08 07 06 05 04 04 03 02
+	00 00 01 02 03 05 06 07
 ]
 
 @font_hex ( 0-F ) 

projects/examples/dev.time.usm

@@ -17,7 +17,6 @@
 |0100 ;System { vector 2 pad 6 r 2 g 2 b 2 }
 |0120 ;Screen { vector 2 width 2 height 2 pad 2 x 2 y 2 color 1 }
 |0130 ;Sprite { vector 2 pad 6 x 2 y 2 addr 2 color 1 }
-|0180 ;Audio { ch1adsr 2 ch2adsr 2 ch3adsr 2 ch4adsr 2 ch1vol 1 ch1pitch 1 ch2vol 1 ch2pitch 1 ch3vol 1 ch3pitch 1 ch4vol 1 ch4pitch 1 }
 |01a0 ;Time { year 2 month 1 day 1 hour 1 minute 1 second 1 dow 1 doy 2 isdst 1 get 1 }
 
 ( program )
@@ -27,12 +26,6 @@
 	( theme ) #0ff8 =System.r #0f08 =System.g #0f08 =System.b
 	( vectors ) ,FRAME =Screen.vector
 
-	#1000 =Audio.ch1adsr
-	#66 =Audio.ch1vol
-
-	#0003 =Audio.ch2adsr
-	#66 =Audio.ch2vol
-
 BRK
 
 @FRAME
@@ -43,13 +36,6 @@ BRK
 	~Time.second ~current.second NEQ #01 JNZ BRK
 	~Time.second =current.second
 
-	( play sounds )
-	#0d =Audio.ch1pitch
-
-	~Time.second #0f MOD #00 NEQ ^$no-tone JNZ
-		#0d #02 MUL =Audio.ch2pitch
-	$no-tone
-
 	( clear )
 	#0080 SCALEX #0080 SCALEY ~needles.sx ~needles.sy #00 ,draw-line JSR2
 	#0080 SCALEX #0080 SCALEY ~needles.mx ~needles.my #00 ,draw-line JSR2

src/apu.c

@@ -0,0 +1,164 @@
+#include <SDL2/SDL.h>
+#include <stdlib.h>
+
+/*
+Copyright (c) 2021 Devine Lu Linvega
+Copyright (c) 2021 Andrew Alderwick
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE.
+*/
+
+#include "uxn.h"
+
+#define SAMPLE_FREQUENCY 48000
+
+extern SDL_AudioDeviceID audio_id;
+int error(char *msg, const char *err);
+
+static Uint32 note_advances[12] = {
+	0x82d01286 / (SAMPLE_FREQUENCY / 30), /* C7 */
+	0x8a976073 / (SAMPLE_FREQUENCY / 30),
+	0x92d5171d / (SAMPLE_FREQUENCY / 30), /* D7 */
+	0x9b904100 / (SAMPLE_FREQUENCY / 30),
+	0xa4d053c8 / (SAMPLE_FREQUENCY / 30), /* E7 */
+	0xae9d36b0 / (SAMPLE_FREQUENCY / 30), /* F7 */
+	0xb8ff493e / (SAMPLE_FREQUENCY / 30),
+	0xc3ff6a72 / (SAMPLE_FREQUENCY / 30), /* G7 */
+	0xcfa70054 / (SAMPLE_FREQUENCY / 30),
+	0xdc000000 / (SAMPLE_FREQUENCY / 30), /* A7 */
+	0xe914f623 / (SAMPLE_FREQUENCY / 30),
+	0xf6f11003 / (SAMPLE_FREQUENCY / 30) /* B7 */
+};
+
+typedef struct {
+	Uint16 *dat;
+	Uint8 i, n, sz, ends;
+} Queue;
+
+typedef struct {
+	Uint32 count, advance, period;
+	Uint16 vector;
+	Sint16 start_value, end_value;
+	Queue queue;
+} WaveformGenerator;
+
+typedef struct {
+	WaveformGenerator wv[2];
+	Sint8 volume[2], playing;
+} Note;
+
+static Note *notes = NULL;
+static int n_notes = 0;
+static Queue *q;
+static Uint16 id_addr;
+
+static void
+play_note(Uxn *u, int note_i, Sint16 *samples, int n_samples)
+{
+	int i;
+	Note *note = &notes[note_i];
+	while(n_samples--) {
+		Sint32 sample = 1;
+		for(i = 0; i < 2; ++i) {
+			WaveformGenerator *wv = &note->wv[i];
+			q = &wv->queue;
+			wv->count += wv->advance;
+			while(wv->count > wv->period) {
+				wv->count -= wv->period;
+				wv->start_value = wv->end_value;
+				if(q->i == q->n) {
+					q->i = q->n = 0;
+					if(!q->ends) {
+						u->ram.dat[id_addr] = note_i;
+						evaluxn(u, wv->vector);
+					}
+				}
+				if(!q->n) {
+					note->playing = 0;
+					return;
+				}
+				wv->end_value = (Sint16)q->dat[q->i++];
+				wv->period = (30 << 4) * q->dat[q->i++];
+			}
+			if(wv->period >> 9)
+				sample *= wv->start_value + (Sint32)(wv->end_value - wv->start_value) * (Sint32)(wv->count >> 10) / (Sint32)(wv->period >> 10);
+			else
+				sample *= wv->end_value;
+		}
+		for(i = 0; i < 2; ++i)
+			*(samples++) += sample / 0xf * note->volume[i] / 0x10000;
+	}
+}
+
+static void
+play_all_notes(void *u, Uint8 *stream, int len)
+{
+	int i;
+	SDL_memset(stream, 0, len);
+	for(i = 0; i < n_notes; ++i)
+		if(notes[i].playing) play_note(u, i, (Sint16 *)stream, len >> 2);
+	q = NULL;
+}
+
+static Note *
+get_note(Uint8 i)
+{
+	if(i >= n_notes) notes = SDL_realloc(notes, (i + 1) * sizeof(Note));
+	while(i >= n_notes) SDL_zero(notes[n_notes++]);
+	return &notes[i];
+}
+
+static Uint8
+audio_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)
+{
+	Uint8 *m = u->ram.dat + ptr;
+	int i;
+	if(b0 == 0xa) {
+		Note *note = get_note(b1);
+		note->playing = 1;
+		for(i = 0; i < 2; ++i) {
+			note->volume[i] = 0xf & (m[0x8] >> 4 * (1 - i));
+			note->wv[i].vector = (m[0x0 + i * 2] << 8) + m[0x1 + i * 2];
+			note->wv[i].count = note->wv[i].period = 0;
+			note->wv[i].end_value = 0;
+			note->wv[i].queue.n = note->wv[i].queue.i = 0;
+			note->wv[i].queue.ends = 0;
+		}
+		note->wv[0].advance = note_advances[m[0x9] % 12] >> (8 - m[0x9] / 12);
+		note->wv[1].advance = (30 << 20) / SAMPLE_FREQUENCY;
+	} else if(b0 == 0xe && q != NULL) {
+		if(q->n == q->sz) {
+			q->sz = q->sz < 4 ? 4 : q->sz * 2;
+			q->dat = SDL_realloc(q->dat, q->sz * sizeof(*q->dat));
+		}
+		q->dat[q->n++] = (m[0xb] << 8) + m[0xc];
+		q->dat[q->n++] = (m[0xd] << 8) + b1;
+	} else if(b0 == 0xf && q != NULL) {
+		q->ends = 1;
+		return b1;
+	}
+}
+
+int
+initapu(Uxn *u, Uint8 id)
+{
+	SDL_AudioSpec as;
+	SDL_zero(as);
+	as.freq = SAMPLE_FREQUENCY;
+	as.format = AUDIO_S16;
+	as.channels = 2;
+	as.callback = play_all_notes;
+	as.samples = 2048;
+	as.userdata = u;
+	audio_id = SDL_OpenAudioDevice(NULL, 0, &as, NULL, 0);
+	if(!audio_id)
+		return error("Audio", SDL_GetError());
+	id_addr = portuxn(u, id, "audio", audio_poke)->addr + 0xa;
+	SDL_PauseAudioDevice(audio_id, 0);
+	return 1;
+}

src/emulator.c

@@ -15,6 +15,9 @@ WITH REGARD TO THIS SOFTWARE.
 
 #include "uxn.h"
 
+int initapu(Uxn *u, Uint8 id);
+void stepapu(Uxn *u);
+
 #define HOR 48
 #define VER 32
 #define PAD 2
@@ -49,38 +52,12 @@ Uint8 font[][8] = {
 	{0x00, 0x7e, 0x40, 0x7c, 0x40, 0x40, 0x7e, 0x00},
 	{0x00, 0x7e, 0x40, 0x40, 0x7c, 0x40, 0x40, 0x00}};
 
-#define SAMPLE_FREQUENCY 48000
-
-static Uint32 note_periods[12] = {
-	/* middle C (C4) is note 60 */
-	(Uint32)0xfa7e * SAMPLE_FREQUENCY, /* C-1 */
-	(Uint32)0xec6f * SAMPLE_FREQUENCY,
-	(Uint32)0xdf2a * SAMPLE_FREQUENCY, /* D-1 */
-	(Uint32)0xd2a4 * SAMPLE_FREQUENCY,
-	(Uint32)0xc6d1 * SAMPLE_FREQUENCY, /* E-1 */
-	(Uint32)0xbba8 * SAMPLE_FREQUENCY, /* F-1 */
-	(Uint32)0xb120 * SAMPLE_FREQUENCY,
-	(Uint32)0xa72f * SAMPLE_FREQUENCY, /* G-1 */
-	(Uint32)0x9dcd * SAMPLE_FREQUENCY,
-	(Uint32)0x94f2 * SAMPLE_FREQUENCY, /* A-1 */
-	(Uint32)0x8c95 * SAMPLE_FREQUENCY,
-	(Uint32)0x84b2 * SAMPLE_FREQUENCY /* B-1 */
-};
-
-typedef struct audio_channel {
-	Uint32 period, count;
-	Sint32 age, a, d, s, r;
-	Sint16 value[2];
-	Sint8 volume[2], phase;
-} Channel;
-Channel channels[4];
-
 static SDL_Window *gWindow;
 static SDL_Renderer *gRenderer;
 static SDL_Texture *gTexture;
-static SDL_AudioDeviceID audio_id;
+SDL_AudioDeviceID audio_id;
 static Screen screen;
-static Device *devsystem, *devscreen, *devmouse, *devkey, *devctrl, *devaudio;
+static Device *devsystem, *devscreen, *devmouse, *devkey, *devctrl;
 
 #pragma mark - Helpers
 
@@ -241,61 +218,6 @@ togglezoom(Uxn *u)
 	redraw(pixels, u);
 }
 
-Sint16
-audio_envelope(Channel *c)
-{
-	if(c->age < c->a)
-		return 0x0888 * c->age / c->a;
-	else if(c->age < c->d)
-		return 0x0444 * (2 * c->d - c->a - c->age) / (c->d - c->a);
-	else if(c->age < c->s)
-		return 0x0444;
-	else if(c->age < c->r)
-		return 0x0444 * (c->r - c->age) / (c->r - c->s);
-	else
-		return 0x0000;
-}
-
-void
-audio_callback(void *userdata, Uint8 *stream, int len)
-{
-	Sint16 *samples = (Sint16 *)stream;
-	int i, j;
-	len >>= 2; /* use len for number of samples, not bytes */
-	for(j = len * 2 - 1; j >= 0; --j) samples[j] = 0;
-	for(i = 0; i < 4; ++i) {
-		Channel *c = &channels[i];
-		if(c->period < (1 << 20)) continue;
-		for(j = 0; j < len; ++j) {
-			c->age += 1;
-			c->count += 1 << 20;
-			while(c->count > c->period) {
-				Sint16 mul;
-				c->count -= c->period;
-				c->phase = !c->phase;
-				mul = (c->phase * 2 - 1) * audio_envelope(c);
-				c->value[0] = mul * c->volume[0];
-				c->value[1] = mul * c->volume[1];
-			}
-			samples[j * 2] += c->value[0];
-			samples[j * 2 + 1] += c->value[1];
-		}
-	}
-	(void)userdata;
-}
-
-void
-silence(void)
-{
-	int i;
-	for(i = 0; i < 4; ++i) {
-		Channel *c = &channels[i];
-		c->volume[0] = 0;
-		c->volume[1] = 0;
-		c->period = 0;
-	}
-}
-
 void
 quit(void)
 {
@@ -313,7 +235,6 @@ quit(void)
 int
 init(void)
 {
-	SDL_AudioSpec as;
 	if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0)
 		return error("Init", SDL_GetError());
 	gWindow = SDL_CreateWindow("Uxn", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, WIDTH * ZOOM, HEIGHT * ZOOM, SDL_WINDOW_SHOWN);
@@ -328,18 +249,8 @@ init(void)
 	if(!(pixels = (Uint32 *)malloc(WIDTH * HEIGHT * sizeof(Uint32))))
 		return error("Pixels", "Failed to allocate memory");
 	clear(pixels);
-	silence();
 	SDL_StartTextInput();
 	SDL_ShowCursor(SDL_DISABLE);
-	as.freq = SAMPLE_FREQUENCY;
-	as.format = AUDIO_S16;
-	as.channels = 2;
-	as.callback = audio_callback;
-	as.samples = 2048;
-	audio_id = SDL_OpenAudioDevice(NULL, 0, &as, NULL, 0);
-	if(!audio_id)
-		return error("Audio", SDL_GetError());
-	SDL_PauseAudioDevice(audio_id, 0);
 	screen.x1 = PAD * 8;
 	screen.x2 = WIDTH - PAD * 8 - 1;
 	screen.y1 = PAD * 8;
@@ -504,29 +415,6 @@ file_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)
 	return b1;
 }
 
-Uint8
-audio_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)
-{
-	Uint8 *m = u->ram.dat;
-	m[PAGE_DEVICE + 0x0070 + b0] = b1;
-	if(b0 > 0x08 && b0 & 1) {
-		Uint16 addr = ptr + (b0 & 0x6);
-		Channel *c = &channels[(b0 & 0x6) >> 1];
-		SDL_LockAudioDevice(audio_id);
-		c->period = note_periods[m[addr + 9] % 12] >> (m[addr + 9] / 12);
-		c->count %= c->period;
-		c->volume[0] = (m[addr + 8] >> 4) & 0xf;
-		c->volume[1] = m[addr + 8] & 0xf;
-		c->age = 0;
-		c->a = (SAMPLE_FREQUENCY >> 4) * ((m[addr] >> 4) & 0xf);
-		c->d = c->a + (SAMPLE_FREQUENCY >> 4) * (m[addr] & 0xf);
-		c->s = c->d + (SAMPLE_FREQUENCY >> 4) * ((m[addr + 1] >> 4) & 0xf);
-		c->r = c->s + (SAMPLE_FREQUENCY >> 4) * (m[addr + 1] & 0xf);
-		SDL_UnlockAudioDevice(audio_id);
-	}
-	return b1;
-}
-
 Uint8
 midi_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)
 {
@@ -586,9 +474,13 @@ start(Uxn *u)
 	while(1) {
 		SDL_Event event;
 		double elapsed, start = SDL_GetPerformanceCounter();
+		SDL_LockAudioDevice(audio_id);
 		while(SDL_PollEvent(&event) != 0) {
 			switch(event.type) {
-			case SDL_QUIT: quit(); break;
+			case SDL_QUIT:
+				SDL_UnlockAudioDevice(audio_id);
+				quit();
+				break;
 			case SDL_MOUSEBUTTONUP:
 			case SDL_MOUSEBUTTONDOWN:
 			case SDL_MOUSEMOTION:
@@ -611,6 +503,7 @@ start(Uxn *u)
 			}
 		}
 		evaluxn(u, devscreen->vector);
+		SDL_UnlockAudioDevice(audio_id);
 		if(screen.reqdraw)
 			redraw(pixels, u);
 		elapsed = (SDL_GetPerformanceCounter() - start) / (double)SDL_GetPerformanceFrequency() * 1000.0f;
@@ -641,7 +534,8 @@ main(int argc, char **argv)
 	devkey = portuxn(&u, 0x05, "key", ppnil);
 	devmouse = portuxn(&u, 0x06, "mouse", ppnil);
 	portuxn(&u, 0x07, "file", file_poke);
-	devaudio = portuxn(&u, 0x08, "audio", audio_poke);
+	if(!initapu(&u, 0x08))
+		return 1;
 	portuxn(&u, 0x09, "midi", ppnil);
 	portuxn(&u, 0x0a, "datetime", datetime_poke);
 	portuxn(&u, 0x0b, "---", ppnil);