libgambatte: initial psg div reset re work

libgambatte/src/initstate.cpp

@@ -1198,10 +1198,9 @@ void gambatte::setInitState(SaveState &state, bool const cgb, bool const gbaCgbM
 	state.mem.ioamhram.ptr[0x140] = 0x91;
 	state.mem.ioamhram.ptr[0x144] = 0x00;
 
-	// The next div update will be determined by the cycle counter low bits.
-	// This also applies to the TIMA and PSG frame sequencer, which may suggest
-	// that div reset could affect the other two.
-	// TODO: test whether div reset can affect other counters.
+	// DIV, TIMA, and the PSG frame sequencer are clocked by bits of the
+	// cycle counter less divLastUpdate (equivalent to a counter that is
+	// reset on DIV write).
 	state.mem.divLastUpdate = -0x1C00;
 	state.mem.timaLastUpdate = 0;
 	state.mem.tmatime = disabled_time;

libgambatte/src/memory.cpp

@@ -690,6 +690,8 @@ void Memory::nontrivial_ff_write(unsigned const p, unsigned data, unsigned long
 		data |= 0x7E - isCgb() * 2;
 		break;
 	case 0x04:
+		psg_.generateSamples(cc, isDoubleSpeed());
+		psg_.divReset();
 		tima_.divReset(cc, TimaInterruptRequester(intreq_));
 		return;
 	case 0x05:

libgambatte/src/sound.cpp

@@ -67,6 +67,13 @@ void PSG::reset() {
 	ch4_.reset();
 }
 
+void PSG::divReset() {
+	ch1_.divReset();
+	ch2_.divReset();
+	ch3_.divReset();
+	ch4_.divReset();
+}
+
 void PSG::setStatePtrs(SaveState &state) {
 	ch3_.setStatePtrs(state);
 }

libgambatte/src/sound.h

@@ -31,6 +31,7 @@ public:
 	PSG();
 	void init(bool cgb);
 	void reset();
+	void divReset();
 	void setStatePtrs(SaveState &state);
 	void saveState(SaveState &state);
 	void loadState(SaveState const &state);

libgambatte/src/sound/channel1.cpp

@@ -186,6 +186,17 @@ void Channel1::reset() {
 	setEvent();
 }
 
+void Channel1::divReset() {
+	unsigned long const cc = cycleCounter_;
+	cycleCounter_ = (cc & -0x1000) + 2 * (cc & 0x800);
+	dutyUnit_.divReset(cc, cycleCounter_);
+	setEvent();
+	while (cycleCounter_ >= nextEventUnit_->counter()) {
+		nextEventUnit_->event();
+		setEvent();
+	}
+}
+
 void Channel1::init(bool cgb) {
 	sweepUnit_.init(cgb);
 }

libgambatte/src/sound/channel1.h

@@ -42,6 +42,7 @@ public:
 	bool isActive() const { return master_; }
 	void update(uint_least32_t *buf, unsigned long soBaseVol, unsigned long cycles);
 	void reset();
+	void divReset();
 	void init(bool cgb);
 	void saveState(SaveState &state);
 	void loadState(SaveState const &state);

libgambatte/src/sound/channel2.cpp

@@ -92,6 +92,17 @@ void Channel2::reset() {
 	setEvent();
 }
 
+void Channel2::divReset() {
+	unsigned long const cc = cycleCounter_;
+	cycleCounter_ = (cc & -0x1000) + 2 * (cc & 0x800);
+	dutyUnit_.divReset(cc, cycleCounter_);
+	setEvent();
+	while (cycleCounter_ >= nextEventUnit->counter()) {
+		nextEventUnit->event();
+		setEvent();
+	}
+}
+
 void Channel2::saveState(SaveState &state) {
 	dutyUnit_.saveState(state.spu.ch2.duty, cycleCounter_);
 	envelopeUnit_.saveState(state.spu.ch2.env);

libgambatte/src/sound/channel2.h

@@ -40,6 +40,7 @@ public:
 	bool isActive() const { return master_; }
 	void update(uint_least32_t *buf, unsigned long soBaseVol, unsigned long cycles);
 	void reset();
+	void divReset();
 	void saveState(SaveState &state);
 	void loadState(SaveState const &state);
 

libgambatte/src/sound/channel3.cpp

@@ -91,6 +91,17 @@ void Channel3::reset() {
 	sampleBuf_ = 0;
 }
 
+void Channel3::divReset() {
+	unsigned long const cc = cycleCounter_;
+	cycleCounter_ = (cc & -0x1000) + 2 * (cc & 0x800);
+	if (waveCounter_ != SoundUnit::counter_disabled)
+		waveCounter_ -= cc - cycleCounter_;
+
+	lastReadTime_ -= cc - cycleCounter_;
+	if (cycleCounter_ >= lengthCounter_.counter())
+		lengthCounter_.event();
+}
+
 void Channel3::init(bool cgb) {
 	cgb_ = cgb;
 }

libgambatte/src/sound/channel3.h

@@ -32,6 +32,7 @@ public:
 	Channel3();
 	bool isActive() const { return master_; }
 	void reset();
+	void divReset();
 	void init(bool cgb);
 	void setStatePtrs(SaveState &state);
 	void saveState(SaveState &state) const;

libgambatte/src/sound/channel4.cpp

@@ -108,6 +108,13 @@ void Channel4::Lfsr::reset(unsigned long cc) {
 	backupCounter_ = cc + toPeriod(nr3_);
 }
 
+void Channel4::Lfsr::divReset(unsigned long oldCc, unsigned long newCc) {
+	updateBackupCounter(oldCc);
+	backupCounter_ -= oldCc - newCc;
+	if (counter_ != counter_disabled)
+		counter_ -= oldCc - newCc;
+}
+
 void Channel4::Lfsr::resetCounters(unsigned long oldCc) {
 	updateBackupCounter(oldCc);
 	backupCounter_ -= counter_max;
@@ -195,6 +202,17 @@ void Channel4::reset() {
 	setEvent();
 }
 
+void Channel4::divReset() {
+	unsigned long const cc = cycleCounter_;
+	cycleCounter_ = (cc & -0x1000) + 2 * (cc & 0x800);
+	lfsr_.divReset(cc, cycleCounter_);
+	setEvent();
+	while (cycleCounter_ >= nextEventUnit_->counter()) {
+		nextEventUnit_->event();
+		setEvent();
+	}
+}
+
 void Channel4::saveState(SaveState &state) {
 	lfsr_.saveState(state, cycleCounter_);
 	envelopeUnit_.saveState(state.spu.ch4.env);

libgambatte/src/sound/channel4.h

@@ -40,6 +40,7 @@ public:
 	bool isActive() const { return master_; }
 	void update(uint_least32_t *buf, unsigned long soBaseVol, unsigned long cycles);
 	void reset();
+	void divReset();
 	void saveState(SaveState &state);
 	void loadState(SaveState const &state);
 
@@ -53,6 +54,7 @@ private:
 		void nr3Change(unsigned newNr3, unsigned long cc);
 		void nr4Init(unsigned long cc);
 		void reset(unsigned long cc);
+		void divReset(unsigned long oldCc, unsigned long newCc);
 		void saveState(SaveState &state, unsigned long cc);
 		void loadState(SaveState const &state);
 		void disableMaster() { killCounter(); master_ = false; reg_ = 0x7FFF; }

libgambatte/src/sound/duty_unit.cpp

@@ -115,6 +115,15 @@ void DutyUnit::reset() {
 	setCounter();
 }
 
+void DutyUnit::divReset(unsigned long cc, unsigned long newCc) {
+	if (nextPosUpdate_ == counter_disabled)
+		return;
+
+	updatePos(cc);
+	nextPosUpdate_ -= cc - newCc;
+	setCounter();
+}
+
 void DutyUnit::saveState(SaveState::SPU::Duty &dstate, unsigned long const cc) {
 	updatePos(cc);
 	setCounter();

libgambatte/src/sound/duty_unit.h

@@ -35,6 +35,7 @@ public:
 	void nr3Change(unsigned newNr3, unsigned long cc);
 	void nr4Change(unsigned newNr4, unsigned long cc);
 	void reset();
+	void divReset(unsigned long cc, unsigned long newCc);
 	void saveState(SaveState::SPU::Duty &dstate, unsigned long cc);
 	void loadState(SaveState::SPU::Duty const &dstate, unsigned nr1, unsigned nr4, unsigned long cc);
 	void killCounter();

test/hwtests/sound/ch1_div_write_reset_length_counter_timing_nr52_1_dmg08_cgb04c_outF1.asm

@@ -0,0 +1,123 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch1_div_write_reset_length_counter_timing_nr52_2_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,124 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch1_late_div_write_nr52_1a_dmg08_cgb04c_outF1.asm

@@ -0,0 +1,128 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch1_late_div_write_nr52_1b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,129 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch1_late_div_write_nr52_2a_dmg08_cgb04c_outF1.asm

@@ -0,0 +1,126 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch1_late_div_write_nr52_2b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,127 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(11), a
+	ld a, f0
+	ldff(12), a
+	ld a, 00
+	ldff(13), a
+	ld a, c7
+	ldff(14), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_div_write_reset_length_counter_timing_nr52_1_dmg08_cgb04c_outF2.asm

@@ -0,0 +1,123 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_div_write_reset_length_counter_timing_nr52_2_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,124 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_late_div_write_nr52_1a_dmg08_cgb04c_outF2.asm

@@ -0,0 +1,128 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_late_div_write_nr52_1b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,129 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_late_div_write_nr52_2a_dmg08_cgb04c_outF2.asm

@@ -0,0 +1,126 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch2_late_div_write_nr52_2b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,127 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(16), a
+	ld a, f0
+	ldff(17), a
+	ld a, 00
+	ldff(18), a
+	ld a, c7
+	ldff(19), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_div_write_reset_length_counter_timing_nr52_1_dmg08_cgb04c_outF4.asm

@@ -0,0 +1,125 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+	ld b, ed
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_div_write_reset_length_counter_timing_nr52_2_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,126 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+	ld b, ed
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_late_div_write_nr52_1a_dmg08_cgb04c_outF4.asm

@@ -0,0 +1,129 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+
+.text@546
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_late_div_write_nr52_1b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,130 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+
+.text@546
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_late_div_write_nr52_2a_dmg08_cgb04c_outF4.asm

@@ -0,0 +1,127 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+
+.text@547
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch3_late_div_write_nr52_2b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,128 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ldff(1a), a
+	ld a, fd
+	ldff(1b), a
+	ld a, f0
+	ldff(1c), a
+	ld a, 00
+	ldff(1d), a
+	ld a, c7
+	ldff(1e), a
+
+.text@547
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_div_write_reset_length_counter_timing_nr52_1_dmg08_cgb04c_outF8.asm

@@ -0,0 +1,123 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_div_write_reset_length_counter_timing_nr52_2_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,124 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+	ld b, ee
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_late_div_write_nr52_1a_dmg08_cgb04c_outF8.asm

@@ -0,0 +1,128 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_late_div_write_nr52_1b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,129 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+
+.text@547
+	ldff(04), a
+	ld b, f6
+	ld c, 0a
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_late_div_write_nr52_2a_dmg08_cgb04c_outF8.asm

@@ -0,0 +1,126 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+

test/hwtests/sound/ch4_late_div_write_nr52_2b_dmg08_cgb04c_outF0.asm

@@ -0,0 +1,127 @@
+.size 8000
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	xor a, a
+	ldff(04), a
+	ldff(24), a
+	ldff(25), a
+	ldff(26), a
+	ld a, 80
+	ldff(26), a
+	ld a, 3d
+	ldff(20), a
+	ld a, f0
+	ldff(21), a
+	ld a, 00
+	ldff(22), a
+	ld a, c7
+	ldff(23), a
+
+.text@548
+	ldff(04), a
+	ld b, f8
+	ld c, 08
+lwait:
+	dec b
+	jrnz lwait
+	dec c
+	jrnz lwait
+	nop
+	nop
+	ldff a, (26)
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, 00
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	pop af
+	ld b, a
+	swap a
+	and a, 0f
+	ld(9800), a
+	ld a, b
+	and a, 0f
+	ld(9801), a
+	ld a, c0
+	ldff(47), a
+	ld a, 80
+	ldff(68), a
+	ld a, ff
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	ldff(69), a
+	xor a, a
+	ldff(69), a
+	ldff(69), a
+	ldff(43), a
+	ld a, 91
+	ldff(40), a
+lprint_limbo:
+	jr lprint_limbo
+
+.text@7400
+lwaitly_b:
+	ld c, 44
+lwaitly_b_loop:
+	ldff a, (c)
+	cmp a, b
+	jrnz lwaitly_b_loop
+	ret
+
+.data@7a00
+	00 00 7f 7f 41 41 41 41
+	41 41 41 41 41 41 7f 7f
+	00 00 08 08 08 08 08 08
+	08 08 08 08 08 08 08 08
+	00 00 7f 7f 01 01 01 01
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 01 01 01 01
+	3f 3f 01 01 01 01 7f 7f
+	00 00 41 41 41 41 41 41
+	7f 7f 01 01 01 01 01 01
+	00 00 7f 7f 40 40 40 40
+	7e 7e 01 01 01 01 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 41 41 41 41 7f 7f
+	00 00 7f 7f 01 01 02 02
+	04 04 08 08 10 10 10 10
+	00 00 3e 3e 41 41 41 41
+	3e 3e 41 41 41 41 3e 3e
+	00 00 7f 7f 41 41 41 41
+	7f 7f 01 01 01 01 7f 7f
+	00 00 08 08 22 22 41 41
+	7f 7f 41 41 41 41 41 41
+	00 00 7e 7e 41 41 41 41
+	7e 7e 41 41 41 41 7e 7e
+	00 00 3e 3e 41 41 40 40
+	40 40 40 40 41 41 3e 3e
+	00 00 7e 7e 41 41 41 41
+	41 41 41 41 41 41 7e 7e
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 7f 7f
+	00 00 7f 7f 40 40 40 40
+	7f 7f 40 40 40 40 40 40
+