; NVMX DIZC
; |||| ||||
; |||| |||+- Carry
; |||| ||+-- Zero
; |||| |+--- Interrupt Disable
; |||| +---- Decimal Mode
; |||+------ Index Register Size (0 = 16 bit, 1 = 8-bit)
; ||+------- Accumulator Size (0 = 16 bit, 1 = 8-bit)
; |+-------- Overflow
; +--------- Negative

.p816		; Enable SNES instruction set

.include "registers.inc"

.segment "ZEROPAGE"

temp_addr:		.res 2

joypad_press:	.res 2
joypad_hold:	.res 2
joypad_prev:	.res 2

inidisp:		.res 1
obj_sel:		.res 1
bg_mode:		.res 1
mosaic:			.res 1
bg1_sc:			.res 1
bg2_sc:			.res 1
bg3_sc:			.res 1
bg4_sc:			.res 1
cg_wsel:		.res 1
cg_adsub:		.res 1
tm:				.res 1
ts:				.res 1
memsel:			.res 1
nmitimen:		.res 1
bg1_scroll_x:	.res 2
bg2_scroll_x:	.res 2
bg3_scroll_x:	.res 2
bg4_scroll_x:	.res 2
bg1_scroll_y:	.res 2
bg2_scroll_y:	.res 2
bg3_scroll_y:	.res 2
bg4_scroll_y:	.res 2
wh0:			.res 1
wh1:			.res 1
wh2:			.res 1
wh3:			.res 1
mdma_en:		.res 1
hdma_en:		.res 1

main_loop_done:	.res 1

.segment "RAM"

.include "lorom128.inc"

.segment "BANK0"

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

RESET:
	CLC					; Set native mode
	XCE
	SEI
	CLD
	SEP #$30			; Set A/X/Y to 8 bit
	.a8
	.i8

	LDA #$80			; Enable FBlank
	STA INIDISP
	STZ MEMSEL
	STZ NMITIMEN		; Disable interrupts and auto-joypad
	STZ MDMAEN			; Stop DMAs
	STZ HDMAEN

	LDX #$00
	INX

MemClear:
	STZ WMADDL			; Set WRAM address for DMA
	STZ WMADDM
	STX WMADDH

	LDA #%00001000		; Set DMA with fixed Source
	STA DMAP0

	LDA #$80			; Set DMA destination to $2180
	STA BBAD0

	LDA #$18			; Set DMA source to $00:8018
	STA A1T0L			; This points to $00 in 'LDX #$00'
	LDA #$80
	STA A1T0H
	STZ A1B0

	LDA #$FF			; Set DMA transfer to $FFFF bytes
	STA DAS0L
	STA DAS0H
	LDA #%00000001

	STA MDMAEN			; Start DMA transfer
	DEX					; Decrement X and loop to clear the second page
	BPL MemClear

	LDA #$00
	TCD					; Set Direct Page
	PHA
	PLB					; Pull Data Bank
	TAX
	DEX
	TXS					; Set Stack Pointer

	JSR RegisterSetup

LoadGraphics:
	.i16				; Set for compiled, REP #$10 is in subroutine above
	LDX #$C000
	STX VMADDL			; Set VRAM address for DMA to $C000

	LDA #%00000001		; Set DMA mode to write to two registers
	STA DMAP0

	LDA #$18			; Set DMA destination to $2118
	STA BBAD0

	STZ A1T0L			; Set DMA source to $01:0000
	STZ A1T0H
	LDA #$01
	STA A1B0

	LDA #$FF			; Set DMA transfer to $FFFF bytes
	STA DAS0L
	STA DAS0H
	LDA #%00000001

	STA MDMAEN			; Start DMA transfer

	LDA #$80
	STA CGADD

	SEP #$10
	.i8

	REP #$20
	.a16

	LDX #$03
	PHX
	PLB

	LDX #$00

:	LDA PaletteZangetsu,X
	STA CGDATA
	INX
	INX
	CMP #$20
	BNE :-

	LDA #$81			; Enable NMI and auto-joypad
	STA nmitimen
	STA NMITIMEN

	SEP #$30
	.a8
	.i8

MainLoop:








	LDX #$01
	STX main_loop_done

NMIWait:
	LDX main_loop_done
	BNE NMIWait
	JMP MainLoop

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

RegisterSetup:
	REP #$10
	.i16

	LDX #$0000
	LDA #$80			; Enable FBlank
	STA inidisp
	STA INIDISP
	LDA #$03			; Object Size 8x8 and 16x16, OAM 1 at $C000, OAM 2 at $E000
	STA obj_sel
	STA OBSEL
	STX OAMADDL			; Reset OAM address (OAMADDL/H)

	LDA #$09			; BG Mode 1 with BG3 priority
	STA bg_mode
	STA BGMODE
	STZ MOSAIC

	LDA #%00000011		; 2x2 tilemap starting from $0000
	STA bg1_sc
	STA BG1SC
	LDA #%00010011		; 2x2 tilemap starting from $2000
	STA bg2_sc
	STA BG2SC
	LDA #%01011001		; 2x1 tilemap starting from $B000
	STA bg3_sc
	STA BG3SC
	STZ BG4SC
	LDA #$22			; Set BG 1 & 2 CHR address to $4000
	STA BG12NBA
	LDA #$05			; Set BG 3 CHR address to $A000
	STA BG34NBA

	STZ BG1HOFS			; Reset scroll positions
	STZ BG1HOFS
	STZ BG1VOFS
	STZ BG1VOFS
	STZ BG2HOFS
	STZ BG2HOFS
	STZ BG2VOFS
	STZ BG2VOFS
	STZ BG3HOFS
	STZ BG3HOFS
	STZ BG3VOFS
	STZ BG3VOFS
	STZ BG4HOFS
	STZ BG4HOFS
	STZ BG4VOFS
	STZ BG4VOFS

	STZ VMAIN			; Reset video port controls
	STX VMADDL			; Reset VRAM address (VMADDL/H)

	STZ M7SEL			; Reset Mode 7 settings
	LDA #$01
	STA M7A				; Set $0001 to Mode 7 A & B parameters
	STZ M7A
	STA M7B
	STZ M7B
	STZ M7C				; Set Mode 7 parameters C, D, X & Y to $0000
	STZ M7C
	STZ M7D
	STZ M7D
	STZ M7X
	STZ M7X
	STZ M7Y
	STZ M7Y

	STZ CGADD			; Reset CGRAM address
	STZ W12SEL			; Reset Window Mask settings
	STZ W34SEL
	STZ WOBJSEL
	STZ WH0
	STZ WH1
	STZ WH2
	STZ WH3
	STZ WBGLOG
	STZ WOBJLOG
	STZ TM				; Reset main and sub-screen settings
	STZ TS
	STZ TMW
	STZ TSW
	STZ CGWSEL
	STZ CGADSUB
	LDA #$E0			; Set fixed color data to black
	STA COLDATA

	STZ SETINI			; Reset screen mode
	STZ WMADDL
	STZ WMADDM
	STZ WMADDH
	STZ HTIMEL			; Clear H/VBlank counters
	STZ HTIMEH
	STZ VTIMEL
	STZ VTIMEH
	RTS

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

NMI:
	PHA
	PHX
	PHY

	LDA main_loop_done
	BEQ SkipNMI

	REP #$10
	.i16





:	LDA HVBJOY
	AND #$01
	BEQ :-
	LDX JOY1L
	STX joypad_hold

	; Add press and release

	STZ main_loop_done

SkipNMI:
	PLY
	PLX
	PLA
	RTI

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

IRQ:
	PHA
	PHX
	PHY

	PLY
	PLX
	PLA
	RTI

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

ABORT:
COPROCESSOR:
BREAK:
	RTI

;;================================================================================================================================;;
;;--------------------------------------------------------------------------------------------------------------------------------;;
;;================================================================================================================================;;

.segment "BANK1"

	.incbin "graphics0.chr"
	.incbin "graphics1.chr"

.segment "BANK2"

	.incbin "graphics2.chr"
	.incbin "graphics3.chr"

.segment "BANK3"

PaletteZangetsu:
	.word $0000,$577F,$31DF,$39CE,$0014,$7F95,$7E4B,$0000,$7E39,$7810,$7F3A,$7FFF,$7DFE,$4C08,$59DF,$6F1F