git.joshuawise.com / fpgaboy.git / blame
| Commit | Line | Data |
|---|---|---|
| 49c326da | 1 | SECTION "boot", HOME[$0] |
| 1eefdc8e | 2 | boot: ld a, $AA |
| 49c326da | 3 | ld [$FF51], A ; Poke the LEDs |
| 1eefdc8e JW |
4 | |
| 5 | ld sp, $FFFE | |
| 6 | ||
| 7 | ld hl, signon | |
| 8 | call puts | |
| 49c326da JW |
9 | |
| 10 | ; Write a little bit to the RAM | |
| 1eefdc8e JW |
11 | ld hl, $0104 |
| 12 | xor a | |
| 49c326da JW |
13 | ld [HLI], A |
| 14 | ld [HLI], A | |
| 15 | ld [HLI], A | |
| 16 | ld [HLI], A | |
| 17 | ld [HLI], A | |
| 18 | ld [HLI], A | |
| 19 | ld [HLI], A | |
| 20 | ld [HLI], A | |
| 21 | ||
| 49c326da JW |
22 | ld A, $FF |
| 23 | ld [HLI], A | |
| 24 | ld [HLI], A | |
| 25 | ld [HLI], A | |
| 26 | ld [HLI], A | |
| 27 | ld [HLI], A | |
| 28 | ld [HLI], A | |
| 29 | ld [HLI], A | |
| 30 | ld [HLI], A | |
| 31 | ||
| 1eefdc8e | 32 | ld c, $51 |
| 49c326da | 33 | |
| 1eefdc8e JW |
34 | .wait: ld a, [c] |
| 35 | cp $00 | |
| 36 | jr nz, .wait | |
| 37 | ||
| 38 | ld h, a | |
| 39 | ld l, a | |
| 40 | ld [hl], $01 ; Select the GB boot rom | |
| 41 | ||
| 42 | ld a, $55 | |
| 43 | ld [c], a | |
| 44 | ||
| 45 | ld hl, booting | |
| 46 | call puts | |
| 47 | ||
| 48 | rst $00 ; Boot | |
| 49 | ||
| 50 | putc: | |
| 51 | ld c, $53 | |
| 52 | push af | |
| 53 | .waitport: | |
| 54 | ld a,[c] | |
| 55 | cp $00 | |
| 56 | jr nz,.waitport | |
| 57 | pop af | |
| 58 | ld [$FF52],a | |
| 59 | ret | |
| 60 | ||
| 61 | puts: | |
| 62 | ld a, [hli] | |
| 63 | cp $00 | |
| 64 | ret z | |
| 65 | call putc | |
| 66 | jr puts | |
| 67 | ||
| 68 | signon: | |
| 69 | db $0D,$0A,$1B,"[1mFPGABoy Boot ROM",$1B,"[0m",$0D,$0A,0 | |
| 70 | booting: | |
| 71 | db "Booting...",$0D,$0A,0 | |
| 72 | ||
| 73 | ||
| 49c326da JW |
74 | SECTION "a", HOME[$100] |
| 75 | nop ; Make sure we don't overflow. | |
| 76 |