snes-asm/legacy/test_gfx/my_custom.asm

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NASM
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.MACRO Spin_Loop ARGS XCOUNT
ldx #XCOUNT
lvl3\@:
lda #$ff
lvl2\@:
xba
lda #$ff
lvl1\@:
dea
cmp #$00
bne lvl1\@
xba
dea
cmp #$00
bne lvl2\@
dex
txa
cmp #$00
bne lvl3\@
.ENDM
.MACRO Set_A_8_XY_16
; 16-bit xy, 8-bit a
rep #%00010000
sep #%00100000
.ENDM
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.MACRO Reset_Palette_Offset
stz $2121
.ENDM
.MACRO Load_Palette_Color ARGS BYTE1 BYTE2
lda #BYTE1
sta $2122
lda #BYTE2
sta $2122
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.ENDM
.MACRO Set_Screen_Brightness
lda #\1
sta $2100 ; $2100 is the screen brightness register
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.ENDM
.MACRO Enable_NMI_And_Joypad
lda #%10000001
sta $4200
.ENDM
; loads, in a loop, an alternating grid of tiles
.MACRO Tile_Load_Loop
ldx #$0400 ; load $0400 (VRAM address of tile data)
TileLoadLoop:
stx $2116 ; store VRAM address of tile data to VRAM address word-sized register
lda #$01 ; smile tile
sta $2118 ;store tile map entry to the address specified in $2116 - this increments or not based on 2115
inx
stx $2116
lda #$00 ; blank tile
sta $2118
inx
cpx #$0780 ; $400 - $780 seems to be limit of snes screen tile memory
bne TileLoadLoop
.ENDM