snes-asm/test_gfx.asm

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.include "header.inc"
.include "snes_init.asm"
.include "my_custom.asm"
.BANK 0 SLOT 0
.org 0
.section "Vblank"
VBlank:
rti
.ENDS
.BANK 0 SLOT 0
.ORG 0
.section "Main"
.MACRO Video_Port_Control
;VRAM transfer, word-access, increment by 1
lda #%10000000
sta $2115
.ENDM
;assumes 8-bit a, 16-bit xy
.MACRO Load_Block_to_VRAM ARGS SOURCE DEST SIZE
Video_Port_Control
ldx #DEST
stx $2116 ; $2116/2117 is 2byte address for VRAM upload/download. most significant bit must be 0
lda #:SOURCE ; source bank
ldx #SOURCE ; source offset
ldy #SIZE
stx $4302 ; store data offset into DMA control register
sta $4304 ; store bank into DMA source bank
sty $4305 ; store size of block
lda #$01
sta $4300 ; set DMA mode (word, normal increment)
lda #$18
sta $4301 ; set destination register (VRAM write register) - add value to $2100 to get destination address
; i.e. this is writing to $2118, which when written writes a byte to VRAM
lda #$01
sta $420b ; and start the transfer
.ENDM
Start:
Snes_Init
Set_A_8_XY_16
Load_Palette_Color $00, $00
Load_Palette_Color $00, $00
Load_Palette_Color $00, $00
Load_Palette_Color $ff, $0a
Set_Screen_Brightness %00001111
lda #%00000000 ; 8x8 for all 4 backgrounds, no priority flip, Mode: 4 colors/tile w/ 32 palettes
sta $2105 ; store to screen mode register
; size (last argument) depends on color mode
; location is beginning of VRAM
; put character data at VRAM $0000, tile data at $0400
lda #$04
sta $2107 ; BG1 tile map location (upper 6 bits)
lda #$00
sta $210b ; BG1 character location ($1000 word intervals - can't go over $8000 b/c size of VRAM)
stz $1337
; main screen designation
lda #%00000001
sta $212c ; enable bkg 1,
; Load_Block_to_VRAM TileMap, $0400, 16
Load_Block_to_VRAM Tiles, $0000, (8*2*2),
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ldx #$0400 ; load $0400 (VRAM address of tile data)
TileLoadLoop:
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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
lda #%10000001 ; enable NMI and joypads
sta $4200
mainloop:
Spin_Loop $02
Reset_Palette_Offset
Load_Palette_Color $00, $00
Load_Palette_Color $00, $00
Load_Palette_Color $00, $00
Load_Palette_Color $ff, $0a
Spin_Loop $02
Reset_Palette_Offset
Load_Palette_Color $ff, $a0
Load_Palette_Color $00, $00
Load_Palette_Color $00, $00
Load_Palette_Color $ff, $0a
jmp mainloop
.ENDS
.BANK 1 SLOT 0
.org 0
.section "TileData"
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Tiles:
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;blank tile
.db $00, $00, $00, $00, $00, $00, $00, $00
.db $00, $00, $00, $00, $00, $00, $00, $00
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;face
.db %00000000
.db %00000000
.db %11000011
.db %11000011
.db %11000011
.db %11000011
.db %00111000
.db %00111000
.db %00111000
.db %00111000
.db %10000001
.db %10000001
.db %01000010
.db %01000010
.db %00111100
.db %00111100
TileMap:
.db $00, $01
.db $00, $01
.db $00, $01
.db $00, $01
.db $00, $01
.db $00, $01
.db $00, $01
.db $00, $01
.ENDS