From 4f12e8751cd3af6fb85d0cf2d927c32addd0f851 Mon Sep 17 00:00:00 2001 From: Greg Date: Mon, 8 Apr 2013 01:26:49 -0700 Subject: [PATCH] Initial commit, code to make a green screen and infinite-loop --- .gitignore | 3 ++ Makefile | 13 ++++++ README.md | 1 + greenspace.asm | 28 +++++++++++++ greenspace.link | 2 + header.inc | 55 ++++++++++++++++++++++++++ snes_init.asm | 102 ++++++++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 204 insertions(+) create mode 100644 .gitignore create mode 100644 Makefile create mode 100644 README.md create mode 100644 greenspace.asm create mode 100644 greenspace.link create mode 100644 header.inc create mode 100644 snes_init.asm diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..de9ccde --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +*.swp +*.smc +*.obj diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..32838a1 --- /dev/null +++ b/Makefile @@ -0,0 +1,13 @@ +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 diff --git a/README.md b/README.md new file mode 100644 index 0000000..9d18888 --- /dev/null +++ b/README.md @@ -0,0 +1 @@ +Playing around with SNES assembly stuff diff --git a/greenspace.asm b/greenspace.asm new file mode 100644 index 0000000..d12d0e3 --- /dev/null +++ b/greenspace.asm @@ -0,0 +1,28 @@ +.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 diff --git a/greenspace.link b/greenspace.link new file mode 100644 index 0000000..21738aa --- /dev/null +++ b/greenspace.link @@ -0,0 +1,2 @@ +[objects] +greenspace.obj diff --git a/header.inc b/header.inc new file mode 100644 index 0000000..d3dfc61 --- /dev/null +++ b/header.inc @@ -0,0 +1,55 @@ +;==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. diff --git a/snes_init.asm b/snes_init.asm new file mode 100644 index 0000000..0ca63db --- /dev/null +++ b/snes_init.asm @@ -0,0 +1,102 @@ + .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