@@ -72,6 +72,7 @@ BRK

 @on-screen ( -> )

 	;move-head JSR2

+	;draw-vu JSR2

 	.head/pos PEK #08 MOD #00 NEQ ,&skip JNZ

 		;bang JSR2

 	&skip

@@ -421,6 +422,16 @@ RTN

 RTN

+@draw-vu ( -- )

+	.ctlframe/x1 PEK2 #0088 ADD2 .ctlframe/y1 PEK2 #0010 ADD2

+		.Audio/volume DEI DUP STH #04 SFT

+	;draw-knob/force JSR2

+	.ctlframe/x1 PEK2 #0098 ADD2 .ctlframe/y1 PEK2 #0010 ADD2

+		STHr #0f AND

+	;draw-knob/force JSR2

+

+RTN

+

 @draw-channels

 	.chnframe/x1 PEK2 .chnframe/y1 PEK2 .chnframe/x2 PEK2 .chnframe/y2 PEK2 #01 ;line-rect JSR2

@@ -79,3 +79,20 @@ apu_start(Apu *c, Uint16 adsr, Uint8 pitch)

 	else /* sample repeat mode */

 		c->period = NOTE_PERIOD;

 }

+

+Uint8

+apu_get_vu(Apu *c, Apu *end)

+{

+	size_t i;

+	Sint32 sum[2] = {0, 0};

+	for(; c < end; ++c) {

+		if(!c->advance) continue;

+		sum[0] += envelope(c, c->age) * c->volume_l;

+		sum[1] += envelope(c, c->age) * c->volume_r;

+	}

+	for(i = 0; i < 2; ++i) {

+		sum[i] /= 0x800;

+		if(sum[i] > 0xf) sum[i] = 0xf;

+	}

+	return (sum[0] << 4) | sum[1];

+}

@@ -20,8 +20,10 @@ typedef struct {

 	Uint8 *addr;

 	Uint32 count, advance, period, age, a, d, s, r;

 	Uint16 i, len;

-	Uint8 volume_l, volume_r, pitch, repeat;

+	Sint8 volume_l, volume_r;

+	Uint8 pitch, repeat;

 } Apu;

 void apu_render(Apu *c, Sint16 *sample, Sint16 *end);

 void apu_start(Apu *c, Uint16 adsr, Uint8 pitch);

+Uint8 apu_get_vu(Apu *c, Apu *end);

@@ -248,7 +248,10 @@ static void

 audio_talk(Device *d, Uint8 b0, Uint8 w)

 {

 	Apu *c;

-	if(!w) return;

+	if(!w) {

+		if(b0 == 0xe) d->dat[0xe] = apu_get_vu(apu, apu + POLYPHONY);

+		return;

+	}

 	c = &apu[d->dat[0x7] % POLYPHONY];

 	SDL_LockAudioDevice(audio_id);

 	if(b0 == 0x1) c->period -= (Sint16)mempeek16(d->dat, 0x0);