libgambatte: fix an off-by-one

Inspection revealed a likely off-by-one w.r.t. which LYC IRQs may be
prevented by a preceding mode=2 IRQ. Verified by some tests.

libgambatte/src/video/lyc_irq.cpp

@@ -37,7 +37,7 @@ unsigned long schedule(unsigned statReg,
 }
 
 bool lycIrqBlockedByM2OrM1StatIrq(unsigned ly, unsigned statreg) {
-	return ly < lcd_vres && ly > 0
+	return ly <= lcd_vres && ly > 0
 	? statreg & lcdstat_m2irqen
 	: statreg & lcdstat_m1irqen;
 }

test/hwtests/lcdirq_precedence/lcdirqprecedence_lycirq_ly90_lcdstat68_dmg08_cgb04c_out1.asm

@@ -0,0 +1,123 @@
+.size 8000
+
+.text@48
+	ld a, ff
+	ldff(45), a
+	jp lstatint
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	ld a, ff
+	ldff(45), a
+	ld b, 8c
+	call lwaitly_b
+	ld a, 40
+	ldff(41), a
+	xor a, a
+	ldff(0f), a
+	ld a, 02
+	ldff(ff), a
+	ei
+	ld a, b
+	inc a
+	inc a
+	ldff(45), a
+
+.text@1000
+lstatint:
+	ld a, 68
+	ldff(41), a
+	ld a, 90
+	ldff(45), a
+
+.text@10cc
+	xor a, a
+	ldff(0f), a
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	ldff a, (0f)
+	and a, 07
+	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/lcdirq_precedence/lcdirqprecedence_lycirq_ly91_lcdstat68_dmg08_cgb04c_out2.asm

@@ -0,0 +1,123 @@
+.size 8000
+
+.text@48
+	ld a, ff
+	ldff(45), a
+	jp lstatint
+
+.text@100
+	jp lbegin
+
+.data@143
+	80
+
+.text@150
+lbegin:
+	ld a, ff
+	ldff(45), a
+	ld b, 8d
+	call lwaitly_b
+	ld a, 40
+	ldff(41), a
+	xor a, a
+	ldff(0f), a
+	ld a, 02
+	ldff(ff), a
+	ei
+	ld a, b
+	inc a
+	inc a
+	ldff(45), a
+
+.text@1000
+lstatint:
+	ld a, 68
+	ldff(41), a
+	ld a, 91
+	ldff(45), a
+
+.text@10cc
+	xor a, a
+	ldff(0f), a
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	ldff a, (0f)
+	and a, 07
+	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
+