DemoSNES

arch 65816
lorom

; Variables
org $000000
!PlayerX = $00
!PlayerY = $00

org $808000
Reset:
	sei
	clc
	xce

	sep #$20
	rep #$10

	lda #$80
	sta $2100

	lda #%00000000
	sta $2133

	lda #$00
	sta $2101

	lda #$00
	sta $2102
	sta $2103

	lda #%00000000
	sta $2105

	lda #%00000100
	sta $2115

	ldx #$0000
	lda #$00
CleanRAM:
	sta $7E0000, x
	sta $7F0000, x
	inx
	cpx #$FFFF
	bne CleanRAM

	jmp Main

Main:
	jsr WaitVBlank
	jsr LoadCHR
	jsr LoadPalette
	jsr UpdatePlayer
	jsr DrawPlayer
	jmp Main

WaitVBlank:
	lda $4210
	and #$80
	bne WaitVBlank
.Exit:
	rts

LoadCHR:
	lda #$00
	sta $2116
	sta $2117

	ldx #$0000
.LoadCHRLoop:
	lda playertile, x
	sta $2118
	inx
	cpx #$20	; Only loading 1 tile is intentional
	bne .LoadCHRLoop
.Exit:
	rts

LoadPalette:
	lda #$00
	sta $2121

	ldx #$0000
.LoadPalLoop:
	lda playerpal, x
	sta $2122
	inx
	cpx #$20
	bne .LoadPalLoop
.Exit:
	rts

UpdatePlayer:
	lda #$80
	sta !PlayerX
	lda #$70
	sta !PlayerY
.Exit:
	rts

DrawPlayer:
	lda #$10
	sta $212C

	lda !PlayerX
	sta $2104
	lda !PlayerY
	sta $2104
	lda #$00
	sta $2104
	lda #$00
	sta $2104
.Exit:
	rts

playertile:
	incbin "DemoPlayer.chr"
playerpal:
	incbin "DemoPlayer_palette.bin"

NMI:
	rti

IRQ:
	rti

org $00FFC0
db "DEMO                 "
db %00110000
db $00
db $00
db $02
db $00
db $01
db $00
dw $0000
dw $0000

; Native Vectors
org $00FFE4
dw $0000
org $00FFE6
dw $0000
org $00FFE8
dw $0000
org $00FFEA
dw NMI
org $00FFEE
dw IRQ

; Emulation Vectors
org $00FFF4
dw $0000
org $00FFF8
dw $0000
org $00FFFA
dw NMI
org $00FFFC
dw Reset
org $00FFFE
dw IRQ