[fpgaboy.git] / oldrom.asm

        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