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Can use lower case instruction names and hex now
This commit is contained in:
Safiire
parent
e661393e6e
commit
eaa80000b2
@ -23,7 +23,6 @@ An NES assembler for the 6502 microprocessor written in Ruby
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Some Todos:
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- Allow lower case mnemonics in source code
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- Understand how to deal with various mappers
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- Understand how to create multiple banks
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- Get an NSF file playing
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@ -36,8 +35,10 @@ An NES assembler for the 6502 microprocessor written in Ruby
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- Support binary literals ie %10101010
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- Anonymous Label support, (maybe, not sure if I like the idea)
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- Give this project a better name.
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- Create an interactive read eval compile loop?
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Some new additions:
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- Lower case mnemonics and hex digits
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- Ported NES101 tutor to this assembler.
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- Added msb and lsb byte selectors on address labels
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- added .org directive
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@ -12,12 +12,14 @@ module Assembler6502
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class InvalidAddressingMode < StandardError; end
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class AddressOutOfRange < StandardError; end
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Mnemonic = '([A-Z]{3})'
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Hex8 = '\$([A-Z0-9]{2})'
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Hex16 = '\$([A-Z0-9]{4})'
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Mnemonic = '([A-Za-z]{3})'
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Hex8 = '\$([A-Fa-f0-9]{2})'
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Hex16 = '\$([A-Fa-f0-9]{4})'
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Immediate = '\#\$([0-9A-F]{2})'
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Sym = '([a-zZ-Z_][a-zA-Z0-9_]+)'
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Branches = '(BPL|BMI|BVC|BVS|BCC|BCS|BNE|BEQ)'
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Branches = '(BPL|BMI|BVC|BVS|BCC|BCS|BNE|BEQ|bpl|bmi|bvc|bvs|bcc|bcs|bne|beq)'
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XReg = '[Xx]'
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YReg = '[Yy]'
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AddressingModes = {
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:relative => {
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@ -49,13 +51,13 @@ module Assembler6502
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:zero_page_x => {
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:example => 'AAA $FF, X',
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:display => '%s $%.2X, X',
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:regex => /^#{Mnemonic}\s+#{Hex8}\s?,\s?X$/
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:regex => /^#{Mnemonic}\s+#{Hex8}\s?,\s?#{XReg}$/
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},
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:zero_page_y => {
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:example => 'AAA $FF, Y',
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:display => '%s $%.2X, Y',
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:regex => /^#{Mnemonic}\s+#{Hex8}\s?,\s?Y$/
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:regex => /^#{Mnemonic}\s+#{Hex8}\s?,\s?#{YReg}$/
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},
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:absolute => {
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@ -68,15 +70,15 @@ module Assembler6502
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:absolute_x => {
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:example => 'AAA $FFFF, X',
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:display => '%s $%.4X, X',
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:regex => /^#{Mnemonic}\s+#{Hex16}\s?,\s?X$/,
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:regex_label => /^#{Mnemonic}\s+#{Sym}\s?,\s?X$/
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:regex => /^#{Mnemonic}\s+#{Hex16}\s?,\s?#{XReg}$/,
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:regex_label => /^#{Mnemonic}\s+#{Sym}\s?,\s?#{XReg}$/
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},
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:absolute_y => {
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:example => 'AAA $FFFF, Y',
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:display => '%s $%.4X, Y',
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:regex => /^#{Mnemonic}\s+#{Hex16}\s?,\s?Y$/,
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:regex_label => /^#{Mnemonic}\s+#{Sym}\s?,\s?Y$/
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:regex => /^#{Mnemonic}\s+#{Hex16}\s?,\s?#{YReg}$/,
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:regex_label => /^#{Mnemonic}\s+#{Sym}\s?,\s?#{YReg}$/
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},
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:indirect => {
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@ -89,15 +91,15 @@ module Assembler6502
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:indirect_x => {
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:example => 'AAA ($FF, X)',
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:display => '%s ($%.2X, X)',
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:regex => /^#{Mnemonic}\s+\(#{Hex8}\s?,\s?X\)$/,
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:regex_label => /^#{Mnemonic}\s+\(#{Sym}\s?,\s?X\)$/
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:regex => /^#{Mnemonic}\s+\(#{Hex8}\s?,\s?#{XReg}\)$/,
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:regex_label => /^#{Mnemonic}\s+\(#{Sym}\s?,\s?#{XReg}\)$/
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},
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:indirect_y => {
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:example => 'AAA ($FF), Y)',
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:display => '%s ($%.2X), Y',
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:regex => /^#{Mnemonic}\s+\(#{Hex8}\)\s?,\s?Y$/,
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:regex_label => /^#{Mnemonic}\s+\(#{Sym}\)\s?,\s?Y$/
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:regex => /^#{Mnemonic}\s+\(#{Hex8}\)\s?,\s?#{YReg}$/,
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:regex_label => /^#{Mnemonic}\s+\(#{Sym}\)\s?,\s?#{YReg}$/
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}
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}
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@ -235,9 +237,9 @@ module Assembler6502
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arg_16 = symbols[@arg].address
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@arg = case @byte_selector
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when :>
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(arg_16 & 0xFF00) >> 8
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high_byte(arg_16)
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when :<
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arg_16 & 0xFF
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low_byte(arg_16)
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end
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return @arg
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end
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@ -301,6 +303,20 @@ module Assembler6502
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[integer & 0x00FF, (integer & 0xFF00) >> 8]
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end
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####
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## Take the high byte of a 16-bit integer
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def high_byte(word)
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(word & 0xFF00) >> 8
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end
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####
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## Take the low byte of a 16-bit integer
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def low_byte(word)
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word & 0xFF
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end
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end
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end
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374
scroll.asm
374
scroll.asm
@ -30,282 +30,282 @@ sprite:
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.org $C000
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reset:
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SEI
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CLD
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sei
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cld
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; Wait two VBLANKs.
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wait_vb1:
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LDA $2002
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BPL wait_vb1
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lda $2002
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bpl wait_vb1
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wait_vb2:
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LDA $2002
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BPL wait_vb2
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lda $2002
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bpl wait_vb2
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; Clear out RAM.
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LDA #$00
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LDX #$00
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lda #$00
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ldx #$00
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clear_segments:
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STA $00, X
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STA $0100, X
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STA $0200, X
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STA $0300, X
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STA $0400, X
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STA $0500, X
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STA $0600, X
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STA $0700, X
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INX
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BNE clear_segments
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sta $00, X
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sta $0100, X
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sta $0200, X
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sta $0300, X
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sta $0400, X
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sta $0500, X
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sta $0600, X
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sta $0700, X
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inx
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bne clear_segments
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; Reset the stack pointer.
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LDX #$FF
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TXS
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ldx #$FF
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txs
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; Disable all graphics.
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LDA #$00
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STA $2000
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STA $2001
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lda #$00
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sta $2000
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sta $2001
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JSR init_graphics
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JSR init_input
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JSR init_sound
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jsr init_graphics
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jsr init_input
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jsr init_sound
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; Set basic PPU registers. Load background from $0000,
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; sprites from $1000, and the name table from $2000.
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LDA #$88
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STA $2000
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LDA #$1E
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STA $2001
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CLI
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lda #$88
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sta $2000
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lda #$1E
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sta $2001
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cli
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; Transfer control to the VBLANK routines.
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forever:
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JMP forever
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jmp forever
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init_graphics:
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JSR init_sprites
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JSR load_palette
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JSR load_name_tables
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JSR init_scrolling
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RTS
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jsr init_sprites
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jsr load_palette
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jsr load_name_tables
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jsr init_scrolling
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rts
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init_input:
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; The A button starts out not-pressed.
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LDA #$00
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STA $01 ; $01 = A button
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RTS
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lda #$00
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sta $01 ; $01 = A button
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rts
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init_sound:
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; initialize sound hardware
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LDA #$01
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STA $4015
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LDA #$00
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STA $4001
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LDA #$40
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STA $4017
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RTS
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lda #$01
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sta $4015
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lda #$00
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sta $4001
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lda #$40
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sta $4017
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rts
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init_sprites:
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; Clear page #2, which we'll use to hold sprite data
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LDA #$00
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LDX #$00
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lda #$00
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ldx #$00
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sprite_clear1:
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STA $0200, X ; $0200 = sprite
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INX
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BNE sprite_clear1
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sta $0200, X ; $0200 = sprite
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inx
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bne sprite_clear1
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; initialize Sprite 0
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LDA #$70
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STA $0200 ; sprite Y coordinate
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LDA #$01
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STA $0201 ; sprite + 1Pattern number
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STA $0203 ; sprite+3 X coordinate
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lda #$70
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sta $0200 ; sprite Y coordinate
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lda #$01
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sta $0201 ; sprite + 1Pattern number
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sta $0203 ; sprite+3 X coordinate
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; sprite+2, color, stays 0.
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; Set initial value of dx
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LDA #$01
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STA $00 ; dx = $00
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RTS
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lda #$01
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sta $00 ; dx = $00
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rts
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; Load palette into $3F00
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load_palette:
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LDA #$3F
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LDX #$00
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STA $2006
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STX $2006
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lda #$3F
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ldx #$00
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sta $2006
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stx $2006
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loady_loop:
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LDA palette, X
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STA $2007
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INX
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CPX #$20
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BNE loady_loop
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RTS
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lda palette, X
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sta $2007
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inx
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cpx #$20
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bne loady_loop
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rts
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; Jam some text into the first name table (at $2400, thanks to mirroring)
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load_name_tables:
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LDY #$00
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LDX #$04
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LDA #<bg
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STA $10
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LDA #>bg
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STA $11
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LDA #$24
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STA $2006
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LDA #$00
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STA $2006
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ldy #$00
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ldx #$04
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lda #<bg
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sta $10
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lda #>bg
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sta $11
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lda #$24
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sta $2006
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lda #$00
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sta $2006
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go_back:
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LDA ($10), Y
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STA $2007
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INY
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BNE go_back
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INC $11
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DEX
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BNE go_back
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RTS
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lda ($10), Y
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sta $2007
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iny
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bne go_back
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inc $11
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dex
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bne go_back
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rts
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; Clear out the Name Table at $2800 (where we already are. Yay.)
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LDY #$00
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LDX #$04
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LDA #$00
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ldy #$00
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ldx #$04
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lda #$00
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back:
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STA $2007
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INY
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BNE back
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DEX
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BNE back
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RTS
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sta $2007
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iny
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bne back
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dex
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bne back
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rts
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init_scrolling:
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LDA #$F0
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STA $02 ; scroll
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RTS
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lda #$F0
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sta $02 ; scroll
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rts
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update_sprite:
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LDA #>sprite
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STA $4014 ; Jam page $200-$2FF into SPR-RAM
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lda #>sprite
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sta $4014 ; Jam page $200-$2FF into SPR-RAM
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LDA $05 ; sprite+3 Is this right???
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BEQ hit_left
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CMP #$F7
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BNE edge_done
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lda $05 ; sprite+3 Is this right???
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beq hit_left
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cmp #$F7
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bne edge_done
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; Hit right
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LDX #$FF
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STX $00 ; dx
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JSR high_c
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JMP edge_done
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ldx #$FF
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stx $00 ; dx
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jsr high_c
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jmp edge_done
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hit_left:
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LDX #$01
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STX $00 ; dx
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JSR high_c
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ldx #$01
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stx $00 ; dx
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jsr high_c
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edge_done: ; update X and store it.
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CLC
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ADC $00 ; dx
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STA $05 ; sprite+3 Is this right?
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RTS
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clc
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adc $00 ; dx
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sta $05 ; sprite+3 Is this right?
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rts
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react_to_input:
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LDA #$01 ; strobe joypad
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STA $4016
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LDA #$00
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STA $4016
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lda #$01 ; strobe joypad
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sta $4016
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lda #$00
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sta $4016
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LDA $4016 ; Is the A button down?
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lda $4016 ; Is the A button down?
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AND #$01
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BEQ not_a
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LDX $01 ; a
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BNE a_done ; Only react if the A button wasn't down last time.
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STA $01 ; Store the 1 in local variable 'a' so that we this is
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JSR reverse_dx ; only called once per press.
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JMP a_done
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beq not_a
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ldx $01 ; a
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bne a_done ; Only react if the A button wasn't down last time.
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sta $01 ; Store the 1 in local variable 'a' so that we this is
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jsr reverse_dx ; only called once per press.
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jmp a_done
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not_a:
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STA $01 ; A has been released, so put that zero into 'a'.
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sta $01 ; A has been released, so put that zero into 'a'.
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a_done:
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LDA $4016 ; B does nothing
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LDA $4016 ; Select does nothing
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LDA $4016 ; Start does nothing
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LDA $4016 ; Up
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AND #$01
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BEQ not_up
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LDX sprite ; Load Y value
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CPX #$07
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BEQ not_up ; No going past the top of the screen
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DEX
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STX sprite
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lda $4016 ; B does nothing
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lda $4016 ; Select does nothing
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lda $4016 ; Start does nothing
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lda $4016 ; Up
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and #$01
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beq not_up
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ldx sprite ; Load Y value
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cpx #$07
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beq not_up ; No going past the top of the screen
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dex
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stx sprite
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not_up: lda $4016 ; Down
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AND #$01
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BEQ not_dn
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LDX sprite
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CPX #$DF ; No going past the bottom of the screen.
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BEQ not_dn
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INX
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STX sprite
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and #$01
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beq not_dn
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ldx sprite
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cpx #$DF ; No going past the bottom of the screen.
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beq not_dn
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inx
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stx sprite
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not_dn:
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RTS ; Ignore left and right, we don't use 'em
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rts ; Ignore left and right, we don't use 'em
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reverse_dx:
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LDA #$FF
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EOR $00 ; dx
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CLC
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ADC #$01
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STA $00 ; dx
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JSR low_c
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RTS
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lda #$FF
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eor $00 ; dx
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clc
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adc #$01
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sta $00 ; dx
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jsr low_c
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rts
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scroll_screen:
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LDX #$00 ; Reset VRAM
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STX $2006
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STX $2006
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ldx #$00 ; Reset VRAM
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stx $2006
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stx $2006
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LDX $02 ; scroll ; Do we need to scroll at all?
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BEQ no_scroll
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DEX
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STX $02 ; scroll
|
||||
LDA #$00
|
||||
STA $2005 ; Write 0 for Horiz. Scroll value
|
||||
ldx $02 ; scroll ; Do we need to scroll at all?
|
||||
beq no_scroll
|
||||
dex
|
||||
stx $02 ; scroll
|
||||
lda #$00
|
||||
sta $2005 ; Write 0 for Horiz. Scroll value
|
||||
STX $2005 ; Write the value of 'scroll' for Vert. Scroll value
|
||||
|
||||
no_scroll:
|
||||
RTS
|
||||
rts
|
||||
|
||||
low_c:
|
||||
PHA
|
||||
LDA #$84
|
||||
STA $4000
|
||||
LDA #$AA
|
||||
STA $4002
|
||||
LDA #$09
|
||||
STA $4003
|
||||
PLA
|
||||
RTS
|
||||
pha
|
||||
lda #$84
|
||||
sta $4000
|
||||
lda #$AA
|
||||
sta $4002
|
||||
lda #$09
|
||||
sta $4003
|
||||
pla
|
||||
rts
|
||||
|
||||
high_c:
|
||||
PHA
|
||||
LDA #$86
|
||||
STA $4000
|
||||
LDA #$69
|
||||
STA $4002
|
||||
LDA #$08
|
||||
STA $4003
|
||||
PLA
|
||||
RTS
|
||||
pha
|
||||
lda #$86
|
||||
sta $4000
|
||||
lda #$69
|
||||
sta $4002
|
||||
lda #$08
|
||||
sta $4003
|
||||
pla
|
||||
rts
|
||||
|
||||
|
||||
vblank:
|
||||
JSR scroll_screen
|
||||
JSR update_sprite
|
||||
JSR react_to_input
|
||||
jsr scroll_screen
|
||||
jsr update_sprite
|
||||
jsr react_to_input
|
||||
|
||||
irq:
|
||||
RTI
|
||||
rti
|
||||
|
||||
; palette data
|
||||
palette:
|
||||
|
||||
Loading…
Reference in New Issue
Block a user