#include "dma.i65"

GAME_MAIN:
	sep #$20 : .as
	stz $4200 ; inhibit IRQs
	jsr killdma
	jsr waitblank
	jsr waitblank
	jsr waitblank
	jsr waitblank
	jsr waitblank
	jsr snes_init
	jsr spc_upload
	lda #$01
	sta $420d ; fast cpu
	jsr setup_gfx
	jsr colortest
	jsr setup_hdma
	jsr screen_init
	sep #$20 : .as
-	jsr msu1init
	cli
	jsr msu1loop
	sei
	bra -

killdma:
	stz $420b
	stz $420c
	stz $4310
	stz $4311
	stz $4312
	stz $4313
	stz $4314
	stz $4320
	stz $4321
	stz $4322
	stz $4323
	stz $4324
	stz $4330
	stz $4331
	stz $4332
	stz $4333
	stz $4334
	stz $4340
	stz $4341
	stz $4342
	stz $4343
	stz $4344
	stz $4350
	stz $4351
	stz $4352
	stz $4353
	stz $4354
	stz $4360
	stz $4361
	stz $4362
	stz $4363
	stz $4364
	rts




waitblank:
-	lda $4212
	and #$80
	bne -
-	lda $4212
	and #$80
	beq -
	rts

colortest:
	sep #$20 : .as
	rep #$10 : .xl
	stz $2130
	rts

setup_gfx:
	sep #$20 : .as
	rep #$10 : .xl
	stz $4200
	stz $420b
	stz $420c

;clear VRAM
	ldx #$0000
	stx $2116
	DMA0(#$09, #$0000, #^zero, #!zero, #$18)

;copy low tilemap
	ldx #$3F80 ; == 8-bit address $7F00
	stx $2116
	DMA0(#$01, #$100, #^tilemap, #!tilemap, #$18)

;copy high tilemap
	ldx #$7F80 ; == 8-bit address $FF00
	stx $2116
	DMA0(#$01, #$20, #^tilemap2, #!tilemap2, #$18)

;clear OAM tables
	ldx #$0000
	stx $2102
	DMA0(#$08, #544, #^zero, #!zero, #$04)

	rts

screen_init:
	sep #$20 : .as		;8-bit accumulator
	rep #$10 : .xl		;16-bit index
	lda #$13		;mode 3, 16x16
	sta $2105
	lda #$3C		;Tilemap addr 0x7800, 32x32
	sta $2107		;for BG1
	lda #$00		;chr base addr:
	sta $210b		;BG1=0x0000, BG2=0x0000
	lda #$01		;enable BG1
	sta $212c		;BG Main
	lda #$01		;enable none
	sta $212d		;BG Sub
	lda #$20		;Window 1 for color
	sta $2125		;Color window
;	lda #$02		;Window 1 for BG1
;	sta $2123
	lda #$10		;cut off 16 pixels left
	sta $2126
	lda #$ef		;cut off 16 pixels right
	sta $2127
	lda #$40		;enable clipping outside window
	sta $2130
;	lda #$01		;enable clipping for BG1
;	sta $212e
	stz $2121		;reset CGRAM ptr
	lda #$0f
	sta $2100		;screen on, full brightness
	rts

snes_init:
	sep #$20 : .as		;8-bit accumulator
	rep #$10 : .xl		;16-bit index
	stz $4200		;
	lda #$ff
	sta $4201		;
	stz $4202		;
	stz $4203		;
	stz $4204		;
	stz $4205		;
	stz $4206		;
	stz $4207		;
	stz $4208		;
	stz $4209		;
	stz $420a		;
	stz $420b		;
	stz $420c		;
	stz $420d		; FAAAAAST
	lda #$8f
	sta $2100		;INIDISP: force blank
	stz $2101		;
	stz $2102		;
	stz $2103		;
;	stz $2104		; (OAM Data?!)
;	stz $2104		; (OAM Data?!)
	stz $2105		;
	stz $2106		;
	stz $2107		;
	stz $2108		;
	stz $2109		;
	stz $210a		;
	stz $210b		;
	stz $210c		;
	stz $210d		;
	stz $210d		;
	stz $210e		;
	stz $210e		;
	stz $210f		;
	stz $210f		;
	stz $2110		;
	stz $2110		;
	stz $2111		;
	stz $2111		;
	stz $2112		;
	stz $2112		;
	stz $2113		;
	stz $2113		;
	stz $2114		;
	stz $2114		;
	lda #$80		;VRAM addr increment after high byte
	sta $2115		;
	stz $2116		;
	stz $2117		;
;	stz $2118		;(VRAM Data?!)
;	stz $2119		;(VRAM Data?!)
	stz $211a		;
	stz $211b		;
	lda #$01
	sta $211b		;
	stz $211c		;
	stz $211c		;
	stz $211d		;
	stz $211d		;
	stz $211e		;
	sta $211e		;
	stz $211f		;
	stz $211f		;
	stz $2120		;
	stz $2120		;
	stz $2121		;
;	stz $2122		; (CG Data?!)
;	stz $2122		; (CG Data?!)
	stz $2123		;
	stz $2124		;
	stz $2125		;
	stz $2126		;
	stz $2127		;
	stz $2128		;
	stz $2129		;
	stz $212a		;
	stz $212b		;
	stz $212c		;
	stz $212d		;
	stz $212e		;
	stz $212f		;
	stz $2130		;
	stz $2131		;
	lda #$e0		;clear fixed color
	sta $2132		;
	stz $2133		;

	rts