Dual bus processor

[fpgaboy.git] / oldrom.asm

diff --git a/oldrom.asm b/oldrom.asm
new file mode 100644 (file)
index 0000000..1504c71
--- /dev/null
+++ b/oldrom.asm
@@ -0,0 +1,70 @@
+       SECTION "a",HOME
+
+main:
+       ld a, $FF       ; Note that we are alive.
+       ld [$FF51],a
+       
+       ld sp, $DFF0
+       
+       ld hl, $DF81
+       ld a, $80
+       ld [hl], a
+
+       ld c, $07
+       ld a, $04       ;start timer, 4.096KHz
+       ld [c], a
+;diqs: ei
+;      ld a, $80
+;      ld c, $51
+;      ld [c], a
+;      jr diqs
+       call irqhand
+       ei
+coqs: jr coqs
+
+       section "Diq", HOME[$38]
+fuqed:
+       di
+       jr fuqed
+
+       section "fuq",HOME[$100]
+irqhand:
+       PUSH AF
+       PUSH BC
+       PUSH DE
+       PUSH HL
+       
+       xor a
+       ld c, $0F       ; ack the irq
+       ld [c], a
+       
+       ld a, $41       ; print A
+       call putc
+       
+       ld hl, $DF81
+       inc [hl]
+       ld a, [hl]
+       ld c, $51
+       ld [c], a
+
+
+       POP HL
+       POP DE
+       POP BC
+       POP AF
+       RETI
+       db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
+       db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
+       db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
+
+putc:
+       ld b, 0
+       ld c, $50
+       push af
+.waitport:
+       ld a,[c]
+       cp b
+       jr nz,.waitport
+       pop af
+       ld [c],a
+       ret