libgambatte: also test late mode=2 vram reads on the dmg

This is apparently different on the DMG.
Fixes mooneye-gb "lcdon_timing-GS" in "DMG" mode.

libgambatte/src/memory.cpp

@@ -648,7 +648,7 @@ unsigned Memory::nontrivial_read(unsigned const p, unsigned long const cc) {
 				return cart_.romdata(p >> 14)[p];
 
 			if (p < mm_sram_begin) {
-				if (!lcd_.vramAccessible(cc))
+				if (!lcd_.vramReadable(cc))
 					return 0xFF;
 
 				return cart_.vrambankptr()[p];
@@ -1135,7 +1135,7 @@ void Memory::nontrivial_write(unsigned const p, unsigned const data, unsigned lo
 		if (p < mm_sram_begin) {
 			if (p < mm_vram_begin) {
 				cart_.mbcWrite(p, data);
-			} else if (lcd_.vramAccessible(cc)) {
+			} else if (lcd_.vramWritable(cc)) {
 				lcd_.vramChange(cc);
 				cart_.vrambankptr()[p] = data;
 			}

libgambatte/src/video.cpp

@@ -349,7 +349,18 @@ bool LCD::isHdmaPeriod(unsigned long const cc) {
 	return ::isHdmaPeriod(ppu_.lyCounter(), m0TimeOfCurrentLine(cc), cc);
 }
 
-bool LCD::vramAccessible(unsigned long const cc) {
+bool LCD::vramReadable(unsigned long const cc) {
+	if (cc >= eventTimes_.nextEventTime())
+		update(cc);
+
+	return !(ppu_.lcdc() & lcdc_en)
+	    || ppu_.lyCounter().ly() >= lcd_vres
+	    || ppu_.inactivePeriodAfterDisplayEnable(cc + 1 - ppu_.cgb() + isDoubleSpeed())
+	    || ppu_.lyCounter().lineCycles(cc) + isDoubleSpeed() < 76u + 3 * ppu_.cgb()
+	    || cc + 2 >= m0TimeOfCurrentLine(cc);
+}
+
+bool LCD::vramWritable(unsigned long const cc) {
 	if (cc >= eventTimes_.nextEventTime())
 		update(cc);
 

libgambatte/src/video.h

@@ -97,7 +97,8 @@ public:
 	void updateScreen(bool blanklcd, unsigned long cc);
 	void resetCc(unsigned long oldCC, unsigned long newCc);
 	void speedChange(unsigned long cycleCounter);
-	bool vramAccessible(unsigned long cycleCounter);
+	bool vramReadable(unsigned long cycleCounter);
+	bool vramWritable(unsigned long cycleCounter);
 	bool oamReadable(unsigned long cycleCounter);
 	bool oamWritable(unsigned long cycleCounter);
 	void wxChange(unsigned newValue, unsigned long cycleCounter);

test/hwtests/vram_m3/preread_1_dmg08_cgb04c_out0.asm

@@ -0,0 +1,104 @@
+.size 8000
+
+.text@48
+	jp lstatint
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	ld b, 98
+	call lwaitly_b
+	xor a, a
+	ld(8000), a
+	ld a, 01
+	ldff(45), a
+	ld a, 40
+	ldff(41), a
+	ld a, 02
+	ldff(ff), a
+	xor a, a
+	ldff(0f), a
+	ei
+
+.text@1000
+lstatint:
+
+.text@1006
+	ld a, (8000)
+	and a, 03
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	pop af
+	ld(9800), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, a0
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	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
+

test/hwtests/vram_m3/preread_2_dmg08_out3_cgb04c_out0.asm

@@ -0,0 +1,104 @@
+.size 8000
+
+.text@48
+	jp lstatint
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	ld b, 98
+	call lwaitly_b
+	xor a, a
+	ld(8000), a
+	ld a, 01
+	ldff(45), a
+	ld a, 40
+	ldff(41), a
+	ld a, 02
+	ldff(ff), a
+	xor a, a
+	ldff(0f), a
+	ei
+
+.text@1000
+lstatint:
+
+.text@1007
+	ld a, (8000)
+	and a, 03
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	pop af
+	ld(9800), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, a0
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	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
+

test/hwtests/vram_m3/preread_3_dmg08_cgb04c_out3.asm

@@ -0,0 +1,104 @@
+.size 8000
+
+.text@48
+	jp lstatint
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	ld b, 98
+	call lwaitly_b
+	xor a, a
+	ld(8000), a
+	ld a, 01
+	ldff(45), a
+	ld a, 40
+	ldff(41), a
+	ld a, 02
+	ldff(ff), a
+	xor a, a
+	ldff(0f), a
+	ei
+
+.text@1000
+lstatint:
+
+.text@1008
+	ld a, (8000)
+	and a, 03
+	jp lprint_a
+
+.text@7000
+lprint_a:
+	push af
+	ld b, 91
+	call lwaitly_b
+	xor a, a
+	ldff(40), a
+	pop af
+	ld(9800), a
+	ld bc, 7a00
+	ld hl, 8000
+	ld d, a0
+lprint_copytiles:
+	ld a, (bc)
+	inc bc
+	ld(hl++), a
+	dec d
+	jrnz lprint_copytiles
+	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
+