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Initial commit, code to make a green screen and infinite-loop

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Greg 2013-04-08 01:26:49 -07:00
commit 4f12e8751c
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.gitignore vendored Normal file
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*.swp
*.smc
*.obj

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Makefile Normal file
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all: smc
greenspace.obj: greenspace.asm
wla-65816 -vo greenspace.asm greenspace.obj
smc: greenspace.obj
wlalink -vr greenspace.link greenspace.smc
clean:
rm greenspace.obj
rm greenspace.smc

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README.md Normal file
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Playing around with SNES assembly stuff

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greenspace.asm Normal file
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.include "header.inc"
.include "snes_init.asm"
VBlank:
RTI
Start:
Snes_Init ; Initialize the SNES
sep #$20 ; set A register to 8-bit
lda #%10000000 ; force Vblank by turning off screen
sta $2100
; load 16-bit color into color data register $2122
lda #%11100000 ;low byte of green
sta $2122
lda #%00000000 ;high byte of green
sta $2122
lda #%00001111 ; End Vblank set brightness to 0b1111 (=100%)
sta $2100 ; store it to Screen Display Register
; loop forever
Forever:
jmp Forever

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greenspace.link Normal file
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[objects]
greenspace.obj

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header.inc Normal file
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;==LoRom== ; We'll get to HiRom some other time.
.MEMORYMAP ; Begin describing the system architecture.
SLOTSIZE $8000 ; The slot is $8000 bytes in size. More details on slots later.
DEFAULTSLOT 0
SLOT 0 $8000 ; Defines Slot 0's starting address.
.ENDME ; End MemoryMap definition
.ROMBANKSIZE $8000 ; Every ROM bank is 32 KBytes in size
.ROMBANKS 8 ; 2 Mbits - Tell WLA we want to use 8 ROM Banks
.SNESHEADER
ID "SNES" ; 1-4 letter string, just leave it as "SNES"
NAME "SNES Tile Demo " ; Program Title - can't be over 21 bytes,
; "123456789012345678901" ; use spaces for unused bytes of the name.
SLOWROM
LOROM
CARTRIDGETYPE $00 ; $00 = ROM only, see WLA documentation for others
ROMSIZE $08 ; $08 = 2 Mbits, see WLA doc for more..
SRAMSIZE $00 ; No SRAM see WLA doc for more..
COUNTRY $01 ; $01 = U.S. $00 = Japan, that's all I know
LICENSEECODE $00 ; Just use $00
VERSION $00 ; $00 = 1.00, $01 = 1.01, etc.
.ENDSNES
.SNESNATIVEVECTOR ; Define Native Mode interrupt vector table
COP EmptyHandler
BRK EmptyHandler
ABORT EmptyHandler
NMI VBlank
IRQ EmptyHandler
.ENDNATIVEVECTOR
.SNESEMUVECTOR ; Define Emulation Mode interrupt vector table
COP EmptyHandler
ABORT EmptyHandler
NMI EmptyHandler
RESET Start ; where execution starts
IRQBRK EmptyHandler
.ENDEMUVECTOR
.BANK 0 SLOT 0 ; Defines the ROM bank and the slot it is inserted in memory.
.ORG 0 ; .ORG 0 is really $8000, because the slot starts at $8000
.SECTION "EmptyVectors" SEMIFREE
EmptyHandler:
rti
.ENDS
.EMPTYFILL $00 ; fill unused areas with $00, opcode for BRK.
; BRK will crash the snes if executed.

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snes_init.asm Normal file
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.MACRO Snes_Init
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
ldx #$1FFF ; set stack to $1FFF
txs
jsr Init
.ENDM
.bank 0
.section "Snes_Init" SEMIFREE
Init:
sep #$30 ; X,Y,A are 8 bit numbers
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 - #$07ff
lda #$FF ; The top pixel drawn on the screen isn't the top one in the tilemap, it's the one above that.
sta $210E ; Plane 0 scroll y (first 8 bits)
sta $2110 ; Plane 1 scroll y (first 8 bits)
sta $2112 ; Plane 2 scroll y (first 8 bits)
sta $2114 ; Plane 3 scroll y (first 8 bits)
lda #$07 ; Since this could get quite annoying, it's better to edit the scrolling registers to fix this.
sta $210E ; Plane 0 scroll y (last 3 bits) #$0 - #$07ff
sta $2110 ; Plane 1 scroll y (last 3 bits) #$0 - #$07ff
sta $2112 ; Plane 2 scroll y (last 3 bits) #$0 - #$07ff
sta $2114 ; Plane 3 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 $2111 ; Plane 2 scroll x (first 8 bits)
stz $2111 ; Plane 2 scroll x (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
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
rts
.ends