241 lines
8.0 KiB
NASM
241 lines
8.0 KiB
NASM
; 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
|
|
|