@@ -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.."

@@ -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 )

@@ -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

-	#159d =Audio.ch2adsr #88 =Audio.ch2vol

-	#26ae =Audio.ch3adsr #88 =Audio.ch3vol

+	,adsr-envelope =Audio.envelope

+	#00 =adsr.ch1a #40 =adsr.ch1d #80 =adsr.ch1s #c0 =adsr.ch1r #88 =volume.ch1

+	#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

-		#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 PEK2

+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD

+		,adsr #00 ~track.active #04 MUL ADD2 POK2 $no-a

 	DUP #01 NEQ ^$no-d JNZ

-		,Audio #00 ~track.active #02 MUL 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-d

+		,adsr #00 ~track.active #04 MUL ADD2 #0001 ADD2 PEK2

+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD

+		,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

-		#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 PEK2

+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD

+		,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

-		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

+		,adsr #00 ~track.active #04 MUL ADD2 #0003 ADD2 PEK2

+		#10 ~Mouse.state #10 EQU #e0 MUL ADD ADD

+		,adsr #00 ~track.active #04 MUL ADD2 #0003 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

+		,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

-	,font_hex #0060 ADD2 =Sprite.addr

+	~trkframe.y1 #0030 ADD2 =Sprite.y

+	,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

-	,font_hex #0060 ADD2 =Sprite.addr

+	~trkframe.y1 #0068 ADD2 =Sprite.y

+	,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 

-	04 04 03 02 01 00 01 02

+	01 00 00 00 00 01 02 03

+	05 06 07 08 08 08 08 07

 ]

 @knob_offsety [

-	00 01 02 03 04 05 06 07 

-	08 07 06 05 04 04 03 02

+	07 06 05 03 02 01 00 00

+	00 00 01 02 03 05 06 07

 ]

 @font_hex ( 0-F ) 

@@ -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

new file mode 100644

@@ -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;

+}

@@ -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);