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- ; SNES ROM startup code
- ;******************************************************************************
- ;*** Define a special section in case most of the code is not in bank 0. ***
- ;******************************************************************************
- ;STACK EQU $01ff ;CHANGE THIS FOR YOUR SYSTEM
- ;STARTUP SECTION OFFSET $008000
- CODE
- XDEF START
- START:
- XREF ~~main
-
- sei ; Disabled interrupts
- clc ; clear carry to switch to native mode
- xce ; Xchange carry & emulation bit. native mode
- rep #$18 ; Binary mode (decimal mode off), X/Y 16 bit
- LONGI ON
- ldx #$1FFF ; set stack to $1FFF
- txs
- rep #$30
- longa on
- longi on
- ; Init data used for heap
- ; see heap definition below
- XREF ~~_heap_top
- XREF ~~_mem_start
- stz ~~_heap_top
- stz ~~_mem_start
-
- XREF ~~preInit
- jsr >~~preInit
- sep #$30 ; X,Y,A are 8 bit numbers
- LONGA OFF
- LONGI OFF
- lda #$8F ; screen off, full brightness
- sta $2100 ; brightness + screen enable register
- stz $2101 ; Sprite register (size + address in VRAM)
- stz $2102 ; Sprite registers (address of sprite memory [OAM])
- stz $2103 ; "" ""
- stz $2105 ; Mode 0, = Graphic mode register
- stz $2106 ; noplanes, no mosaic, = Mosaic register
- stz $2107 ; Plane 0 map VRAM location
- stz $2108 ; Plane 1 map VRAM location
- stz $2109 ; Plane 2 map VRAM location
- stz $210A ; Plane 3 map VRAM location
- stz $210B ; Plane 0+1 Tile data location
- stz $210C ; Plane 2+3 Tile data location
- stz $210D ; Plane 0 scroll x (first 8 bits)
- stz $210D ; Plane 0 scroll x (last 3 bits) #$0 - #$07ff
- stz $210E ; Plane 0 scroll y (first 8 bits)
- stz $210E ; Plane 0 scroll y (last 3 bits) #$0 - #$07ff
- stz $210F ; Plane 1 scroll x (first 8 bits)
- stz $210F ; Plane 1 scroll x (last 3 bits) #$0 - #$07ff
- stz $2110 ; Plane 1 scroll y (first 8 bits)
- stz $2110 ; Plane 1 scroll y (last 3 bits) #$0 - #$07ff
- stz $2111 ; Plane 2 scroll x (first 8 bits)
- stz $2111 ; Plane 2 scroll x (last 3 bits) #$0 - #$07ff
- stz $2112 ; Plane 2 scroll y (first 8 bits)
- stz $2112 ; Plane 2 scroll y (last 3 bits) #$0 - #$07ff
- stz $2113 ; Plane 3 scroll x (first 8 bits)
- stz $2113 ; Plane 3 scroll x (last 3 bits) #$0 - #$07ff
- stz $2114 ; Plane 3 scroll y (first 8 bits)
- stz $2114 ; Plane 3 scroll y (last 3 bits) #$0 - #$07ff
- lda #$80 ; increase VRAM address after writing to $2119
- sta $2115 ; VRAM address increment register
- stz $2116 ; VRAM address low
- stz $2117 ; VRAM address high
- stz $211A ; Initial Mode 7 setting register
- stz $211B ; Mode 7 matrix parameter A register (low)
- lda #$01
- sta $211B ; Mode 7 matrix parameter A register (high)
- stz $211C ; Mode 7 matrix parameter B register (low)
- stz $211C ; Mode 7 matrix parameter B register (high)
- stz $211D ; Mode 7 matrix parameter C register (low)
- stz $211D ; Mode 7 matrix parameter C register (high)
- stz $211E ; Mode 7 matrix parameter D register (low)
- sta $211E ; Mode 7 matrix parameter D register (high)
- stz $211F ; Mode 7 center position X register (low)
- stz $211F ; Mode 7 center position X register (high)
- stz $2120 ; Mode 7 center position Y register (low)
- stz $2120 ; Mode 7 center position Y register (high)
- stz $2121 ; Color number register ($0-ff)
- stz $2123 ; BG1 & BG2 Window mask setting register
- stz $2124 ; BG3 & BG4 Window mask setting register
- stz $2125 ; OBJ & Color Window mask setting register
- stz $2126 ; Window 1 left position register
- stz $2127 ; Window 2 left position register
- stz $2128 ; Window 3 left position register
- stz $2129 ; Window 4 left position register
- stz $212A ; BG1, BG2, BG3, BG4 Window Logic register
- stz $212B ; OBJ, Color Window Logic Register (or,and,xor,xnor)
- sta $212C ; Main Screen designation (planes, sprites enable)
- stz $212D ; Sub Screen designation
- stz $212E ; Window mask for Main Screen
- stz $212F ; Window mask for Sub Screen
- lda #$30
- sta $2130 ; Color addition & screen addition init setting
- stz $2131 ; Add/Sub sub designation for screen, sprite, color
- lda #$E0
- sta $2132 ; color data for addition/subtraction
- stz $2133 ; Screen setting (interlace x,y/enable SFX data)
- stz $4200 ; Enable V-blank, interrupt, Joypad register
- lda #$FF
- sta $4201 ; Programmable I/O port
- stz $4202 ; Multiplicand A
- stz $4203 ; Multiplier B
- stz $4204 ; Multiplier C
- stz $4205 ; Multiplicand C
- stz $4206 ; Divisor B
- stz $4207 ; Horizontal Count Timer
- stz $4208 ; Horizontal Count Timer MSB (most significant bit)
- stz $4209 ; Vertical Count Timer
- stz $420A ; Vertical Count Timer MSB
- stz $420B ; General DMA enable (bits 0-7)
- stz $420C ; Horizontal DMA (HDMA) enable (bits 0-7)
- stz $420D ; Access cycle designation (slow/fast rom)
- cli ; Enable interrupts
- rep #$30
- longa on
- longi on
- jsr >~~main
- brk
- XDEF IRQ
- IRQ:
- XREF ~~IRQHandler
- LONGA ON
- LONGI ON
- rep #$30
- pha
- phx
- phy
- jsr ~~IRQHandler
- ply
- plx
- pla
- rti
-
- XDEF NMI
- NMI:
- XREF ~~NMIHandler
- LONGA ON
- LONGI ON
- rep #$30
- pha
- phx
- phy
- phd
- phb
- lda #$0000
- sep #$30 ; X,Y,A are 8 bit numbers
- LONGA OFF
- LONGI OFF
- lda $4210 ; Read NMI
- LONGA ON
- LONGI ON
- rep #$30
- jsr ~~NMIHandler
- plb
- pld
- ply
- plx
- pla
- rti
-
- DIRQ:
- rti
- ENDS
- ;******************************************************************************
- ;*** Heap definition ***
- ;******************************************************************************
- DATA
- XDEF ~~heap_start
- XDEF ~~heap_end
- ~~heap_start:
- WORD $1000
- ~~heap_end:
- WORD $1200
- ;******************************************************************************
- ;*** SNES ROM Registartion Data ***
- ;******************************************************************************
- REGISTRATION_DATA SECTION
- MAKER_CODE FCC /FF/
- GAME_CODE FCC /SMWJ/
- FIXED_VALUE0 BYTE $00, $00, $00, $00, $00, $00, $00
- EXPANSION_RAM_SIZE BYTE $00
- SPECIAL_VERSION BYTE $00
- CARTRIDGE_TYPE_SUB BYTE $00
- GAME_TITLE FCC /GAME TITLE !/
- ;012345678901234567890;
- MAP_MODE BYTE $20
- CARTRIDGE_SIZE BYTE $00
- ROM_SIZE BYTE $09
- RAM_SIZE BYTE $00
- DESTINATION_CODE BYTE $00
- FIXED_VALUE1 BYTE $33
- MASK_ROM_VERSION BYTE $00
- COMPLEMENT_CHECK BYTE $00, $00
- CHEKSUM BYTE $00, $00
- ;******************************************************************************
- ;*** SNES Interrupts and Reset vector ***
- ;******************************************************************************
- VECTORS SECTION
- ; Native vector
- N_COP DW DIRQ
- N_BRK DW DIRQ
- N_ABORT DW DIRQ
- N_NMI DW NMI
- N_RSRVD DW DIRQ
- N_IRQ DW IRQ
- DS 4
- ; Emulation vector
- E_COP DW DIRQ
- E_RSRVD DW DIRQ
- E_ABORT DW DIRQ
- E_NMI DW DIRQ
- E_RESET DW START
- E_IRQ DW DIRQ
- END
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