Working tic tac toe demo

from
https://wiki.superfamicom.org/snes/show/Making+a+Small+Game+-+Tic-Tac-Toe

minus the input parts, but showing a thing on the screen

tic_tac.asm

@@ -17,16 +17,202 @@ VBlank:
 Start:
     Snes_Init
 
-sep #$30        ; get 8-bit registers
+; 16-bit xy, 8-bit a
-stz $2121       ; write to CGRAM from $0
+rep #%00010000
-lda #%10000000  ; this is
+sep #%00100000
-ldx #%00111100  ; a green color
+
-sta $2122       ; write it
+
-stx $2122       ; to CGRAM
+ldx #$0000
-lda #%00001111  ; turn on screen
+- lda UntitledPalette.l, x
-sta $2100       ; here
+sta $2122
+inx
+cpx #8
+bne -
+
+lda #33
+sta $2121
+lda.l Palette2
+sta $2122
+lda.l Palette2 + 1
+sta $2122
+
+ldx #UntitledData
+lda #:UntitledData
+ldy #(15*16*2)
+
+;$43X0 is DMA register X, X from 0 to 7
+stx $4302 ;A address low byte
+sta $4304 ;A address bank
+sty $4305 ;number of bytes to transfer
+
+lda #%00000001 ;set mode transfer words
+sta $4300
+
+lda #$18            ; $211[89]: VRAM data write
+sta $4301           ; set destination
+
+ldy #$0000
+sty $2116
+
+lda #%00000001
+sta $420b ;start DMA
+
+
+; write to BG1
+
+lda #%10000000 ; VRAM writing mode
+sta $2115
+
+ldx #$4000
+stx $2116 ; write to VRAM
+
+;ugly code starts here - it writes the # shape I mentioned before.
+.rept 2
+   ;X|X|X
+   .rept 2
+     ldx #$0000 ; tile 0 ( )
+     stx $2118
+     ldx #$0002 ; tile 2 (|)
+     stx $2118
+   .endr
+   ldx #$0000
+   stx $2118
+   ;first line finished, add BG's
+   .rept 27
+     stx $2118  ; X=0
+   .endr
+   ;beginning of 2nd line
+   ;-+-+-
+   .rept 2
+     ldx #$0004 ; tile 4 (-)
+     stx $2118
+     ldx #$0006 ; tile 6 (+)
+     stx $2118
+   .endr
+   ldx #$0004   ; tile 4 (-)
+   stx $2118
+   ldx #$0000
+   .rept 27
+     stx $2118
+   .endr
+.endr
+.rept 2
+  ldx #$0000    ; tile 0 ( )
+  stx $2118
+  ldx #$0002    ; tile 2 (|)
+  stx $2118
+.endr
+
+
+
+; BG2 starts at $6000
+ldx #$6000
+stx $2116
+
+ldx #$000c ;and contains one tile
+stx $2118 ;data for VRAM write register
+
+
+
+
+; set up the screen
+
+lda #%00110000 ; 16x16 tiles, mode 0
+sta $2105
+
+lda #%01000000 ; data starts from $4000
+sta $2107      ; for bg1
+
+lda #%0110000 ; and $6000
+sta $2108 ; for bg2
+
+stz $210b	    ; BG1 and BG2 use the $0000 tiles
+
+lda #%00000011  ; enable bg1 and 2
+sta $212C
+
+;The PPU doesn't process the top line, so we scroll down 1 line.
+rep #$20        ; 16bit a
+lda #$07FF      ; this is -1 for BG1
+sep #$20        ; 8bit a
+sta $210E       ; BG1 vert scroll
+xba
+sta $210E
+
+rep #$20        ; 16bit a
+lda #$FFFF      ; this is -1 for BG2
+sep #$20        ; 8bit a
+sta $2110       ; BG2 vert scroll
+xba
+sta $2110
+
+lda #%00001111  ; enable screen, set brightness to 15
+sta $2100
+
+lda #%10000001  ; enable NMI and joypads
+sta $4200
+
+
+
+
+;sep #$30        ; get 8-bit registers
+;stz $2121       ; write to CGRAM from $0
+;lda #%10000000  ; this is
+;ldx #%00111100  ; a green color
+;sta $2122       ; write it
+;stx $2122       ; to CGRAM
+;lda #%00001111  ; turn on screen
+;sta $2100       ; here
+
 
 mainloop:
     jmp mainloop
 
 .ENDS
+
+
+.BANK 1 SLOT 0
+.org 0
+.section "TileData"
+
+UntitledData:
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03
+    .db $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $FF, $FF, $FF, $FF
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $FF, $FF, $FF, $FF
+    .db $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $FF, $FF, $FF, $FF
+    .db $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $FF, $FF, $FF, $FF
+    .db $00, $C0, $00, $E0, $00, $70, $00, $38, $00, $1C, $00, $0E, $00, $07, $00, $03
+    .db $00, $03, $00, $07, $00, $0E, $00, $1C, $00, $38, $00, $70, $00, $E0, $00, $C0
+    .db $00, $07, $00, $0F, $00, $18, $00, $30, $00, $60, $00, $C0, $00, $C0, $00, $C0
+    .db $00, $E0, $00, $F0, $00, $18, $00, $0C, $00, $06, $00, $03, $00, $03, $00, $03
+    .db $FC, $00, $F8, $00, $F0, $00, $E0, $00, $C0, $00, $80, $00, $00, $00, $00, $00
+    .db $3F, $00, $1F, $00, $0F, $00, $07, $00, $03, $00, $01, $00, $00, $00, $00, $00
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03
+    .db $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0
+    .db $FF, $FF, $FF, $FF, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $FF, $FF, $FF, $FF, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00
+    .db $FF, $FF, $FF, $FF, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03, $03
+    .db $FF, $FF, $FF, $FF, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0, $C0
+    .db $00, $03, $00, $07, $00, $0E, $00, $1C, $00, $38, $00, $70, $00, $E0, $00, $C0
+    .db $00, $C0, $00, $E0, $00, $70, $00, $38, $00, $1C, $00, $0E, $00, $07, $00, $03
+    .db $00, $C0, $00, $C0, $00, $C0, $00, $60, $00, $30, $00, $18, $00, $0F, $00, $07
+    .db $00, $03, $00, $03, $00, $03, $00, $06, $00, $0C, $00, $18, $00, $F0, $00, $E0
+    .db $00, $00, $00, $00, $80, $00, $C0, $00, $E0, $00, $F0, $00, $F8, $00, $FC, $00
+    .db $00, $00, $00, $00, $01, $00, $03, $00, $07, $00, $0F, $00, $1F, $00, $3F, $00
+
+UntitledPalette:
+    .db $00, $00, $E0, $7F, $1F, $00, $FF, $03
+Palette2:
+    .db $E0, $7F
+
+; 30 tiles (2 spaces)
+; 480 bytes
+
+.ENDS