Commodore 64 IDE: A Complete Development Tool for Retro Computing
With multiple C64 programming tools, developing your retro computing software has never been faster or more enjoyable! Best of all, it's completely free! No ads, no payments.
C64 IDE — Features
C64 IDE is a full-featured macOS development environment for the Commodore 64, built for developers who want modern tools without losing touch with the hardware they love.
Code Editor
- Syntax highlighting for both Commodore BASIC V2 and 6502 assembly
- Smart keyword recognition — highlights tokens even without spaces, just like the C64 expects (`FORI=0TO15`, `POKE53280,0`)
- Click any keyword to jump instantly to its full reference entry
- Hover over any keyword for an inline tooltip with syntax, description, and examples
- Integrated reference panel with tabs for Commands, Memory, ROM, Colors, PETSCII, and VICE Monitor commands — all searchable
- Full light and dark modes
- Set breakpoints by clicking line numbers — red dot confirms it's set
- Renumber BASIC lines with automatic updating of all GOTO, GOSUB, and THEN references
- Search and replace across all open files
- Up to 10 levels of undo and redo
- Git integration.
- Multi-file project support.
Build System
- One-keystroke build and run — tokenizes BASIC or assembles and links, then launches VICE automatically
- If BASIC65 is chosen as the dialect, will automatically run in xemu instead of vice, making this a first class IDE for MEGA65 BASIC development.
- Integrated ca65 assembler and ld65 linker — no command line required
- Click any build error to jump directly to the offending line in the editor
- Generates full debug symbol files for source-level debugging
- Optional assembly listing file for byte-level verification
- Build output goes into a clean `build/` folder, keeping your source directory tidy
- Compile BASIC programs to ca65-compatible assembly with a single command — great for learning, optimization, or migration
VICE Debugger
- One-keystroke build and debug — launches VICE, connects automatically, and pauses at the start of your program
- As you step through code, the editor scrolls and highlights the current source line in real time
- Full register display (PC, A, X, Y, SP, flags) — updates after every step
- Set and manage breakpoints from both the editor and the debugger window
- Hex memory dump, stack inspection, and inline disassembly
- Type raw VICE monitor commands directly — the full monitor is at your fingertips
- Reference panel automatically switches to the Monitor tab when a debug session starts
- Connect to any already-running VICE instance with remote monitor support
- Cycle count for each opcode visible, both for the current opcode and a cumulative count of all cycles since the start of the program.
Run on Real Hardware
- Deploy directly to an Ultimate 64 or any new-production C64 over your local network — no disk images, no SD cards
- Auto-run option launches your program on the hardware immediately after a successful build
- Deploy and optionally run on a MEGA65 using the etherload command, either C64 BASIC, BASIC65 or assembly.
Sprite Editor
- 24×21 pixel canvas with single-color and multi-color modes
- Multi-frame animation with adjustable FPS and ping-pong playback
- Onion skinning for smooth animation — see the previous frame as a ghost while you draw
- Import from SpritePad (.spd) files or paste raw data in BASIC DATA, assembly .byte, C array, or hex format
- Export as BASIC DATA statements, assembly .byte directives, C arrays, or hex strings
- Flip, shift (with wrap), copy, paste, and duplicate frames
Character Set Editor
- Edit all 256 characters in your custom character set
- Live character map shows the current state of every character as you work
- Live link to the Game Map Editor — changes appear in your map instantly, in real time
- Export individual characters or the full charset as assembly or BASIC DATA
- Load the standard C64 ROM character set as a starting point
- Save and load raw binary charset files
Hi-Res Graphics Editor
- Full 320×200 hi-res bitmap canvas with complete C64 color constraint enforcement
- 160×200 multicolor mode with per-cell color management
- Drawing tools: pencil, eraser, line, rectangle, filled rectangle, oval, filled oval, and flood fill
- Zoom up to 4× for detailed pixel work
- Import Art Studio format files
- Export as Art Studio, raw binary, assembly, BASIC DATA, or a self-displaying PRG that runs standalone on a C64
- Ability to save directly to a D64 disk image
- Raster lines to assist with interrupt scheduling.
Game Map Editor
- 40×25 tile-based map editor — exactly one C64 screen
- Up to 16 layers with independent visibility control
- Live-linked to the Character Set Editor — character changes appear in the map instantly
- Paint, fill, flood, select, and pick tools
- Select tool supports copy and paste with full undo/redo
- Export as assembly, binary, or native .c64map format for later editing
- Raster lines visible to assist with interrupt scheduling.
SID Editor
- Full three-voice SID tracker with per-instrument ADSR envelope, waveform selection, filter, and pulse width control
- Supports triangle, sawtooth, pulse, and noise waveforms — combinable simultaneously
- LP, BP, and HP filter modes, also combinable
- Standard tracker keyboard layout for fast note entry
- Multiple patterns with unlimited pattern count, 32 rows per pattern
- Export music as 6502 assembly or BASIC DATA statements
Image Converter
- Convert any macOS-supported image format (JPEG, PNG, TIFF, etc.) to C64 hi-res or multicolor bitmap
- Floyd-Steinberg, ordered (Bayer), or no dithering
- Real-time brightness and contrast adjustment with full dithering recalculation — what you see is what you get
- Export as Art Studio, raw binary, assembly, BASIC DATA, or self-displaying PRG
- Ability to save directly to a D64 disk image
Disk Image Browser
- Open, create, and manage Commodore 1541 disk images (.d64)
- Open, create, and manage Commodore 1581 disk images (.d81)
- Add, extract, delete, and rename files
- Open BASIC programs directly in the editor
- Machine language files can be automatically disassembled and opened for editing
- Supports .bas, .s, and .prg file types
Tape Image Browser
- Open both .t64 and .tap files
- Full listing of all files in the image
- Extract the prg to a file or open it in the IDE for editing.
- Read, write and create new t64 images.
- Read only support for TAP, no writing or creating new images
6502 Disassembler
- Load any C64 PRG file and disassemble it instantly
- Automatically substitutes descriptive names for known addresses — `JSR CHROUT`, `STA VIC_BORDERCOLOR`, `LDA CIA1_PORTB` — making disassembled code actually readable
- Identifies branch targets and flags illegal/undocumented opcodes
- Export as ca65-compatible assembly, or open directly in the editor as a buildable, runnable project
- Cycle count for each opcode shown on every line to assist with timing.
Reference Tools
PETSCII Character Map — full 256-character interactive reference with decimal, hex, binary, and screen code values, plus plain English descriptions and one-click copy in Dec, Hex, CHR$, POKE, or .byte format
-C64 Character ROM Viewer — browse both built-in character sets with full pixel data, POKE examples, and reversed screen codes
Number Converter — decimal, hex, binary, and octal conversion with clickable bit toggles, bitwise operations (AND, OR, XOR, NOT, SHL, SHR), and common C64 quick-values
- Memory map viewer/editor. See where your programs segments are using memory, then edit them as needed and save your changes.
BASIC Dialect Support
- Built-in support for standard Commodore BASIC V2
- Plugin system for extended BASIC interpreters — syntax highlighting, tokenization, and hover tooltips all update for the active dialect
- Simons' BASIC, Commodore 128 BASIC v7, VisionBASIC, Commander X16 and MEGA65 dialects included as ready-to-use plugins
- Create your own dialect plugins with the built-in Plugin Editor — define keywords, token values, syntax, descriptions, and examples, then save and install with one click
- Share plugins as simple JSON (.c64basic) files
Claude AI Integration
- A Claude tab in the bottom will allow for interactive coding
- Analyze build failures
- Analyze code, both BASIC and assembly
- Suggest improvements
- Create new code on demand
- Aware of C64, C128 and MEGA65 variants (BASIC and assembly) and provides correct help for each.
General
- Universal macOS app — native on both Apple Silicon and Intel
- Dark theme designed for long coding sessions
- Light theme available for those who want it
- Automatically checks for updates daily
- Full undo/redo in every editor and tool window (10 levels)
Current Version 1.6.6
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