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base: greg:379d1c88fcbec9c0e1f549e04cc6df855826af8d
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greg:master
greg:tutorial
greg:modernize
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compare: greg:9794d93fb09cd0c1ee5bffc01f014284646a4782
Branches Tags
greg:master
greg:tutorial
greg:modernize

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379d1c88fc ... 9794d93fb0

2 changed files with 4 additions and 104 deletions
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38
homebrew-tutorial/charset.asm
View File

@ -1,38 +0,0 @@
charset:
; tile 0x00
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
.byte %00000000
; tile 0x01
.byte %11111111 ; row 0, color 0
.byte %00000000 ; row 0, color 1
.byte %10000001 ; row 1, color 0
.byte %00000000 ; row 1, color 1
.byte %10000001 ; row 2, color 0
.byte %00000000 ; row 2, color 1
.byte %10000001 ; row 3, color 0
.byte %00001000 ; row 3, color 1
.byte %10011001 ; row 4, color 0
.byte %00001000 ; row 4, color 1
.byte %10000001 ; row 5, color 0
.byte %00000000 ; row 5, color 1
.byte %10000001 ; row 6, color 0
.byte %00000000 ; row 6, color 1
.byte %11111111 ; row 7, color 0
.byte %00000000 ; row 7, color 1
charset_end:

70
homebrew-tutorial/main.asm
View File

@ -8,79 +8,19 @@
.segment "CODE"
VRAM_CHARS = $0000
VRAM_BG1 = $1000
start:
.include "init.asm"
; Set up the color palette
stz CGADD
; Color 0 - black
lda #$00
sta CGDATA
lda #$00
sta CGDATA
; Color 1 - red
lda #$1f
sta CGDATA
lda #$00
sta CGDATA
; Color 2 - blue
lda #$e0
; Set color zero to some color
; $001f = %0000000000011111
; bbbbbgggggrrrrr
lda #$ff
sta CGDATA
lda #$03
sta CGDATA
; Color 3 - green
lda #$00
sta CGDATA
lda #$7c
sta CGDATA
; Graphics mode 0, 8x8 tiles
stz BGMODE
; Set BG1 and tile map and character data
lda #>VRAM_BG1
sta BG1SC
lda #VRAM_CHARS
sta BG12NBA
; Load character data into VRAM
lda #$80
sta VMAIN
ldx #VRAM_CHARS
stx VMADDL
@charset_loop:
lda charset,x
sta VMDATAL
inx
lda charset,x
sta VMDATAH
inx
cpx #(charset_end - charset)
bne @charset_loop
; write tile to position (1, 1)
TILE_X = 1
TILE_Y = 1
ldx #(VRAM_BG1 + (TILE_Y * 32) + TILE_X)
stx VMADDL
lda #$01 ; tile number
sta VMDATAL
stz VMDATAH
; Show bg1
lda #%00000001
sta TM
lda #$0f
sta INIDISP
@ -91,5 +31,3 @@ nmi:
bit RDNMI
_rti:
rti
.include "charset.asm"