gb_test2

annotate test.asm @ 0:cacfa0888410

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initial commit
author John Tsiombikas <nuclear@member.fsf.org>
date Thu, 10 Jan 2019 04:16:47 +0200
parents
children d63782badb6b
rev   line source
nuclear@0 1 ; vi:ft=rgbasm:
nuclear@0 2 include "hw.inc"
nuclear@0 3
nuclear@0 4 xoffs_center equ 4
nuclear@0 5 yoffs_center equ 12
nuclear@0 6
nuclear@0 7 frame_ptr equ $ff80
nuclear@0 8
nuclear@0 9 section "hdr", ROM0[$100]
nuclear@0 10 nop
nuclear@0 11 jp main
nuclear@0 12
nuclear@0 13 rept $150 - $104
nuclear@0 14 db 0
nuclear@0 15 endr
nuclear@0 16
nuclear@0 17 section "text", ROM0
nuclear@0 18
nuclear@0 19 main:
nuclear@0 20 call init
nuclear@0 21
nuclear@0 22 xor a, a
nuclear@0 23 ldh [frame_ptr], a
nuclear@0 24 .mainloop:
nuclear@0 25 ldh a, [REG_LY]
nuclear@0 26 cp a, 144
nuclear@0 27 jr c, .wait_hsync
nuclear@0 28
nuclear@0 29 ; we're in vsync, increment frame counter and wait for the next frame
nuclear@0 30 ldh a, [frame_ptr]
nuclear@0 31 inc a
nuclear@0 32 ldh [frame_ptr], a
nuclear@0 33 .wait_newframe:
nuclear@0 34 ldh a, [REG_LY]
nuclear@0 35 cp a, 0
nuclear@0 36 jr nz, .wait_newframe
nuclear@0 37
nuclear@0 38 ; scanline code
nuclear@0 39 .wait_hsync:
nuclear@0 40 ldh a, [REG_STAT]
nuclear@0 41 and a, STAT_MODE_MASK
nuclear@0 42 jr nz, .wait_hsync
nuclear@0 43
nuclear@0 44 ldh a, [frame_ptr]
nuclear@0 45 ld d, a
nuclear@0 46
nuclear@0 47 xor a, a
nuclear@0 48 ld b, a
nuclear@0 49 ldh a, [REG_LY]
nuclear@0 50 add a, d
nuclear@0 51 ld c, a
nuclear@0 52
nuclear@0 53 ld hl, sintab
nuclear@0 54 add hl, bc ; hl points to sin value (0-64)
nuclear@0 55
nuclear@0 56 ld a, yoffs_center
nuclear@0 57 add a, [hl]
nuclear@0 58 ldh [REG_SCY], a
nuclear@0 59
nuclear@0 60 ; done, wait until we're out of hsync
nuclear@0 61 .wait_endhsync:
nuclear@0 62 ldh a, [REG_STAT]
nuclear@0 63 and a, STAT_MODE_MASK
nuclear@0 64 jr z, .wait_endhsync
nuclear@0 65
nuclear@0 66 jr .mainloop
nuclear@0 67
nuclear@0 68
nuclear@0 69 di
nuclear@0 70 .end: halt
nuclear@0 71 nop
nuclear@0 72 jp .end
nuclear@0 73
nuclear@0 74 init:
nuclear@0 75 call wait_vsync
nuclear@0 76 xor a, a
nuclear@0 77 ldh [REG_LCDC], a
nuclear@0 78
nuclear@0 79 ; setup identity palette
nuclear@0 80 ld a, $1b
nuclear@0 81 ldh [REG_BGP], a
nuclear@0 82
nuclear@0 83
nuclear@0 84 ; copy tiles
nuclear@0 85 ld hl, $8000
nuclear@0 86 ld de, tiles
nuclear@0 87 ld bc, tiles_end - tiles
nuclear@0 88 .copytiles:
nuclear@0 89 ld a, [de]
nuclear@0 90 ld [hl+], a
nuclear@0 91 inc de
nuclear@0 92 dec bc
nuclear@0 93 ld a, b
nuclear@0 94 or c
nuclear@0 95 jp nz, .copytiles
nuclear@0 96
nuclear@0 97 ; copy tilemap
nuclear@0 98 ld hl, $9800
nuclear@0 99 ld de, tilemap
nuclear@0 100 ld b, 21
nuclear@0 101 .copymap:
nuclear@0 102 ld c, 21
nuclear@0 103 .copymaprow:
nuclear@0 104 ld a, [de]
nuclear@0 105 inc de
nuclear@0 106 ld [hl+], a
nuclear@0 107 dec c
nuclear@0 108 jr nz, .copymaprow
nuclear@0 109
nuclear@0 110 push bc
nuclear@0 111 ld bc, 11
nuclear@0 112 add hl, bc
nuclear@0 113 pop bc
nuclear@0 114
nuclear@0 115 dec b
nuclear@0 116 jr nz, .copymap
nuclear@0 117
nuclear@0 118 ; center viewport
nuclear@0 119 ld a, yoffs_center
nuclear@0 120 ldh [REG_SCY], a
nuclear@0 121 ld a, xoffs_center
nuclear@0 122 ldh [REG_SCX], a
nuclear@0 123
nuclear@0 124 ; configure LCD
nuclear@0 125 ld a, LCDC_DISPON | LCDC_CHAR_8000 | LCDC_BGON
nuclear@0 126 ldh [REG_LCDC], a
nuclear@0 127 ret
nuclear@0 128
nuclear@0 129 wait_vsync:
nuclear@0 130 ldh a, [REG_LY]
nuclear@0 131 cp a, 144
nuclear@0 132 jr c, wait_vsync
nuclear@0 133 ret
nuclear@0 134
nuclear@0 135 section "data", ROM0, align[8]
nuclear@0 136 sintab:
nuclear@0 137 include "sin.inc"
nuclear@0 138
nuclear@0 139 tiles:
nuclear@0 140 incbin "logo.tiles"
nuclear@0 141 tiles_end:
nuclear@0 142 tilemap:
nuclear@0 143 incbin "logo.tilemap"
nuclear@0 144 tilemap_end: