processor 6502
include "vcs.h"
include "macro.h"
seg
org $2000
rorg $f000

switch:
lda $1ff9
repeat 5
nop
repend
lda #$20
sta PF0
lda $1ff8
rts

seg
org $f000
rorg $f000
jsr switch
Temp = $80
;PatternCounter = $81
;ScrollCounter = $82
;FrameCounter = $83
;Change = $84
jsr ResetRAM
lda #%10110000
sta Temp
Reset:
StartFrame:

; Start vertical blank
lda #$00
sta VBLANK
lda #2
sta VSYNC
sta WSYNC
sta WSYNC
sta WSYNC
lda #$00
sta VSYNC

; End of Vertical Sync
ldx #37
vbloop:
sta WSYNC
dex
bne vbloop

;End of vertical blank

; Pre values for 192 scanlines
sta COLUPF
lda #%00000001
; 192 Scanlines of Visible Screen

ldx #192
l1:
stx COLUBK
sta WSYNC
dex
bne l1
; End of Visible Screen
; Start of VBLANK / Overscan
lda #%01000010
ldx #30
sta VBLANK
osloop:
sta WSYNC
dex
bne osloop
jmp StartFrame
ResetRAM:
lda #$00
ldx #$80
resetloop:
sta Temp,x
dex
bne resetloop
rts
coltable:
.byte $01,$02,$03,$04,$05,$06,$07
.byte $0a,$0b,$0c,$0d,$0e,$0f,$10
.byte $13,$14,$15,$16,$17,$18,$19
.byte $1c,$1d,$1e,$1f,$20,$21,$22
.byte $25,$26,$27,$28,$29,$2a,$2b
.byte $2e,$2f,$30,$31,$32,$33,$34
.byte $37,$38,$39,$3a,$3b,$3c,$3d
.byte $40,$41,$42,$43,$44,$45,$46
.byte $49,$4a,$4b,$4c,$4d,$4e,$4f
.byte $52,$53,$54,$55,$56,$57,$58
.byte $5b,$5c,$5d,$5e,$5f,$60,$61
.byte $64,$65,$66,$67,$68,$69,$6a
.byte $6d,$6e,$6f,$70,$71,$72,$73
.byte $76,$77,$78,$79,$7a,$7b,$7c
.byte $7f,$80,$81,$82,$83,$84,$85
.byte $88,$89,$8a,$8b,$8c,$8d,$8e
.byte $91,$92,$93,$94,$95,$96,$97
.byte $9a,$9b,$9c,$9d,$9e,$9f,$a0
.byte $a3,$a4,$a5,$a6,$a7,$a8,$a9
.byte $ac,$ad,$ae,$af,$b0,$b1,$b2
.byte $b5,$b6,$b7,$b8,$b9,$ba,$bb
.byte $bc,$bd,$bc,$bd,$be,$bf
org $fffa
.word Reset
.word Reset
.word Reset
end