@@ -49,11 +49,35 @@ 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 */

+};

+

+static struct audio_channel {

+	Uint32 period, count;

+	int value;

+	Sint16 volume;

+} channels[4];

+

 static SDL_Window *gWindow;

 static SDL_Renderer *gRenderer;

 static SDL_Texture *gTexture;

+static SDL_AudioDeviceID audio_id;

 static Screen screen;

-static Device *devscreen, *devmouse, *devkey, *devctrl;

+static Device *devscreen, *devmouse, *devkey, *devctrl, *devaudio;

 #pragma mark - Helpers

@@ -212,6 +236,28 @@ togglezoom(Uxn *u)

 	redraw(pixels, u);

 }

+void

+audio_callback(void* userdata, Uint8* stream, int len) {

+	Sint16 *samples = (Sint16 *) stream;

+	int i, j;

+	len >>= 1; /* use len for number of samples, not bytes */

+	for (j = 0; j < len; ++j) samples[j] = 0;

+	for (i = 0; i < 4; ++i) {

+		struct audio_channel *c = &channels[i];

+		if (!c->volume) continue;

+		if (c->period < (1 << 20)) continue;

+		for (j = 0; j < len; ++j) {

+			c->count += 1 << 20;

+			while (c->count > c->period) {

+				c->value = !c->value;

+				c->count -= c->period;

+			}

+			samples[j] += (c->value * 2 - 1) * c->volume;

+		}

+	}

+	(void) userdata;

+}

+

 void

 quit(void)

 {

@@ -229,7 +275,8 @@ quit(void)

 int

 init(void)

 {

-	if(SDL_Init(SDL_INIT_VIDEO) < 0)

+	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);

 	if(gWindow == NULL)

@@ -245,6 +292,15 @@ init(void)

 	clear(pixels);

 	SDL_StartTextInput();

 	SDL_ShowCursor(SDL_DISABLE);

+	as.freq = SAMPLE_FREQUENCY;

+	as.format = AUDIO_S16;

+	as.channels = 1;

+	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;

@@ -405,8 +461,16 @@ file_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)

 Uint8

 audio_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)

 {

-	(void)u;

-	printf("%04x - %02x,%02x\n", ptr, b0, b1);

+	Uint8 *m = u->ram.dat;

+	if (b0 & 1) {

+		Uint16 channel_addr = ptr + (b0 & 0x6);

+		struct audio_channel *c = &channels[(b0 & 0x6) >> 1];

+		SDL_LockAudioDevice(audio_id);

+		c->period = note_periods[m[channel_addr + 8] % 12] >> (m[channel_addr + 8] / 12);

+		c->count %= c->period;

+		c->volume = m[channel_addr + 9] << 5;

+		SDL_UnlockAudioDevice(audio_id);

+	}

 	return b1;

 }

@@ -517,7 +581,7 @@ main(int argc, char **argv)

 	devkey = portuxn(&u, "key", ppnil);

 	devmouse = portuxn(&u, "mouse", ppnil);

 	portuxn(&u, "file", file_poke);

-	portuxn(&u, "audio", audio_poke);

+	devaudio = portuxn(&u, "audio", audio_poke);

 	portuxn(&u, "midi", ppnil);

 	portuxn(&u, "datetime", datetime_poke);

 	portuxn(&u, "---", ppnil);