A feature-rich text editor for the Commodore 64.

• BASIC Mode with keyword syntax highlighting and automatic line renumbering
• Smart Paging: 256-line capacity with automatic 64-line pages
• 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 for text editing operations
• Goto Line: Jump directly to any line number in your file
• Mouse Support: Experimental support for Commodore 1351 mouse (click to position cursor)
• Status Bar: Shows filename, cursor position, drive, page, and mode indicators
• 37×23 editing area with line numbers

Install the LLVM-MOS SDK

mkdir build
cd build
cmake ..
cmake --build .

The compiled program will be at build/whisper64.prg

Load on your C64 or emulator:

LOAD "WHISPER64.PRG",8,1
RUN

• F1 → Load file (directory browser)
• F2 → Save file

• CTRL+C → Copy marked text
• CTRL+V → Paste text
• CTRL+Z → Undo
• CTRL+Y → Redo
• CTRL+K → Toggle mark mode
• CTRL+G → Goto line

• F5 → Find text
• F6 → Find & replace
• F7 → Find next

• HOME → Jump to top of file
• Arrow Keys → Move cursor

• CTRL+J → Toggle mouse support (experimental)
• F3 → Select drive (8-15)
• F4 → BASIC mode / Renumber
• F8 → Help screen

Whisper64 includes experimental support for the Commodore 1351 mouse on Control Port 1 (left port).

To use the mouse:

1. Connect your 1351 mouse to Control Port 1
2. Press CTRL+J to enable mouse mode
3. Move the mouse to position the cursor (shown as yellow ^)
4. Click the left button to position the text cursor
5. Press CTRL+J again to disable mouse mode

Notes:

• Mouse cursor is only shown when mouse mode is active
• Clicking in the edit area (lines 1-23) positions the text cursor
• Mouse sensitivity can be adjusted in mouse.c (MOUSE_DIVISOR constant)

Press F4 to enable BASIC mode, which provides:

• Purple keyword highlighting for BASIC commands
• Press F4 again to renumber all lines (10, 20, 30...)
• Automatic update of GOTO, GOSUB, THEN, and ELSE references
• Line number display in cyan

Press F1 to open the directory browser:

• Shows disk name at top
• Displays file type (PRG, SEQ, DEL, USR, REL)
• Shows locked files with asterisk (*)
• Displays block size for each file
• Use ↑/↓ arrows to navigate
• Press RETURN to load selected file
• Press RUN/STOP to cancel

The top status bar displays:

• Filename: Currently loaded/saved file (8 chars)
• Line:Column: Current cursor position
• [BAS]: BASIC mode indicator (purple)
• [M]: Mark mode active indicator (green)
• D:n: Current drive number (cyan)
• Pn/n: Current page / total pages (cyan, if multi-page)

To copy and paste text:

1. Press CTRL+K to enter mark mode
2. Use arrow keys to select text (selection shown in yellow)
3. Press CTRL+C to copy the selected text
4. Move cursor to destination
5. Press CTRL+V to paste
6. Press CTRL+K again to exit mark mode

You can copy up to 8 lines at once. The copied text remains in the clipboard until you copy something new.

Simple Search:

1. Press F5 to open search
2. Type the search term and press RETURN
3. Use F7 to find next occurrence
4. Search wraps around to beginning when reaching end

Find & Replace:

1. First search with F5
2. Press F6 to open replace dialog
3. Type replacement text
4. Choose:
   • Y to replace all occurrences at once
   • N to manually replace each occurrence

1. Press CTRL+G
2. Type the line number (1-64)
3. Press RETURN

Free to use and modify.