]> Joshua Wise's Git repositories - fpgaboy.git/blame_incremental - oldrom.asm
Dual boot ROM support, and the first proof that cellular ram works!
[fpgaboy.git] / oldrom.asm
... / ...
CommitLineData
1 SECTION "a",HOME
2
3main:
4 ld a, $FF ; Note that we are alive.
5 ld [$FF51],a
6
7 ld sp, $DFF0
8
9 ld hl, $DF81
10 ld a, $80
11 ld [hl], a
12
13 ld c, $07
14 ld a, $04 ;start timer, 4.096KHz
15 ld [c], a
16;diqs: ei
17; ld a, $80
18; ld c, $51
19; ld [c], a
20; jr diqs
21 call irqhand
22 ei
23coqs: jr coqs
24
25 section "Diq", HOME[$38]
26fuqed:
27 di
28 jr fuqed
29
30 section "fuq",HOME[$100]
31irqhand:
32 PUSH AF
33 PUSH BC
34 PUSH DE
35 PUSH HL
36
37 xor a
38 ld c, $0F ; ack the irq
39 ld [c], a
40
41 ld a, $41 ; print A
42 call putc
43
44 ld hl, $DF81
45 inc [hl]
46 ld a, [hl]
47 ld c, $51
48 ld [c], a
49
50
51 POP HL
52 POP DE
53 POP BC
54 POP AF
55 RETI
56 db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
57 db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
58 db $18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE,$18,$FE
59
60putc:
61 ld b, 0
62 ld c, $50
63 push af
64.waitport:
65 ld a,[c]
66 cp b
67 jr nz,.waitport
68 pop af
69 ld [c],a
70 ret
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