A text editor for the Commodore 64.
- 80-Column Mode: Bitmap-based 80-column display using a 4x8 pixel font (toggle with CTRL+D)
- REU Support: RAM Expansion Unit for fast page swapping (auto-detected, up to 16MB)
- BASIC Mode with keyword syntax highlighting and automatic line renumbering
- Multi-Page Editing: Pages stored in REU or disk temp files
- Directory Browser: Multi-drive support (8-15) with file type display
- Search & Replace: Find text with wrap-around and replace all
- Copy/Paste: Visual mark mode for selecting and copying text
- Undo/Redo: One-level undo and redo
- Goto Line: Jump to any line number
- Mouse Support: 1351 mouse on Control Port 1
- 40-column mode: 37x23 editing area with line numbers
- 80-column mode: 77x23 editing area with line numbers
Install the LLVM-MOS SDK:
# macOS (Apple Silicon)
curl -sL https://github.com/llvm-mos/llvm-mos-sdk/releases/latest/download/llvm-mos-macos.tar.xz -o /tmp/llvm-mos.tar.xz
mkdir -p ~/llvm-mos && tar -xf /tmp/llvm-mos.tar.xz -C ~/llvm-mos --strip-components=1mkdir build && cd build
cmake -DCMAKE_PREFIX_PATH=~/llvm-mos ..
makeOutput: build/whisper64.prg
A 512KB REU image (whisper64.reu) and a blank D64 disk image (whisper64.d64) are created automatically during the build.
./run_vice.shThis launches VICE (x64sc) with REU enabled and a D64 disk image attached to drive 8.
Transfer whisper64.prg to a disk or SD card and load:
LOAD "WHISPER64",8,1
RUN
For REU support, ensure the REU is connected before starting.
| Key | Function |
|---|---|
| F1 | Load file (directory browser) |
| F2 | Save file |
| F3 | Select drive (8-15) |
| F4 | Toggle BASIC mode / Renumber lines |
| F5 | Find text |
| F6 | Find & replace |
| F7 | Find next |
| F8 | Help screen |
| CTRL+C | Copy marked text |
| CTRL+D | Toggle 40/80 column mode |
| CTRL+G | Goto line |
| CTRL+J | Toggle mouse on/off |
| CTRL+K | Toggle mark mode |
| CTRL+V | Paste text |
| CTRL+W | New file (clear buffer) |
| CTRL+Y | Redo |
| CTRL+Z | Undo |
| HOME | Go to start of file |
| Arrows | Move cursor |
Press CTRL+D to toggle between 40 and 80 column modes.
80-column mode uses VIC-II hires bitmap mode with a 4x8 pixel font (SCREEN-80 from Compute's Gazette, 1984). The display is rendered in VIC bank 3 ($C000-$FFFF) with bitmap data at $E000 and video matrix at $D800.
Limitations:
- Each pair of adjacent characters shares one foreground color
- Slower screen updates than 40-column mode (typing updates only the current line for speed)
The editor auto-detects REU at startup and shows the available size and maximum page count. With REU, page swapping is instant (DMA transfer) instead of using slow disk temp files.
Page capacity depends on REU size:
- 256KB: ~66 pages
- 512KB: ~136 pages
All pages are saved to and loaded from REU when switching pages. File save (F2) writes all pages to disk. File load (F1) reads the file and distributes content across pages as needed.
Press F4 to enable BASIC mode:
- Keyword highlighting in purple
- Press F4 again to renumber lines (10, 20, 30...)
- Updates GOTO, GOSUB, THEN, and ELSE references automatically
Press F1 to open:
- Shows disk name, file types (PRG, SEQ, DEL, USR, REL), block sizes
- UP/DOWN to navigate, RETURN to load, RUN/STOP to cancel
Free to use and modify.