kz80_ws - WordStar Clone for Z80

A WordStar-compatible text editor for the RetroShield Z80. This project generates a Z80 ROM binary that implements a classic WordStar-style text editor with VT100 terminal output.

Features

• Classic WordStar key bindings - Familiar control key sequences for navigation and editing
• VT100/ANSI terminal support - Works with any VT100-compatible terminal
• Block operations - Mark, copy, move, and delete text blocks
• File operations - Save files to SD card storage (via RetroShield I/O)
• Help system - Built-in help screen (^J)
• Status bar - Shows filename, cursor position, insert/overwrite mode, and modified indicator
• WordStar file format - Authentic file format with high-bit word markers

Building

Prerequisites

• Rust toolchain (1.70 or later)
• The retroshield-z80-workbench crate (automatically fetched from crates.io)

Build and Generate ROM

cargo build --release
./target/release/kz80_ws output.bin

Or simply:

cargo run -- output.bin

This generates a Z80 ROM binary file (~4KB) that can be loaded into a RetroShield Z80 or compatible emulator.

Running in the Emulator

# Using the RetroShield emulator
../emulator/rust/target/release/retroshield output.bin

# Or with the TUI debugger (recommended)
../emulator/rust/target/release/retroshield_tui --vt220 output.bin

# Or with the C emulator
../emulator/retroshield output.bin

Key Bindings

Cursor Movement

Arrow keys are also supported via VT100 escape sequences.

Editing

Block Operations (^K prefix)

File Operations (^K prefix)

Quick Commands (^Q prefix)

Other

Screen Layout

+------------------------------------------------------------------+
| Status: filename | L:nnn C:nnn Ins/Ovr [*]                       | <- Row 1
+------------------------------------------------------------------+
| ^K=Block ^Q=Quick ^S=Left ^D=Right ^E=Up ^X=Down ^Y=DelLn ^J=Help | <- Row 2
+------------------------------------------------------------------+
| (separator line)                                                  | <- Row 3
+------------------------------------------------------------------+
|                                                                   |
|                         Text editing area                         | <- Rows 4-22
|                           (19 lines)                              |
|                                                                   |
+------------------------------------------------------------------+
| (separator line)                                                  | <- Row 23
+------------------------------------------------------------------+
| Messages appear here                                              | <- Row 24
+------------------------------------------------------------------+

Memory Map

Technical Details

Terminal Requirements

The editor requires a VT100-compatible terminal with:

• 80x24 minimum screen size
• Cursor positioning (ESC[row;colH)
• Clear screen (ESC[2J)
• Clear to end of line (ESC[K)
• Reverse video (ESC[7m) and reset (ESC[0m)

I/O Ports

WordStar File Format

Files are saved in authentic WordStar format:

• High bit set on last character of each word (for soft hyphenation)
• Soft returns (0x8D 0x0A) for word-wrapped lines
• Hard returns (0x0D 0x0A) for paragraph breaks
• Control codes for formatting: ^B=bold, ^S=underline, ^Y=italic

Limitations

• Maximum ~5KB text buffer
• Maximum 256 lines
• Block operations are line-based only
• Single file editing (no multiple buffers)
• No undo functionality
• No print support

Project Structure

kz80_ws/
├── Cargo.toml          # Rust package configuration
├── LICENSE             # BSD 3-Clause license
├── README.md           # This file
└── src/
    ├── main.rs         # Entry point - generates ROM file
    ├── lib.rs          # Library exports
    └── codegen.rs      # Z80 code generation (~2800 lines)

How It Works

The project uses a code generation approach rather than cross-compilation:

1. Code Generation: The WordStarCodeGen struct builds Z80 machine code by emitting raw bytes
2. Label System: Labels and forward references are tracked and resolved after all code is emitted
3. Standard Library: Uses routines from retroshield-z80-workbench for I/O and terminal control
4. ROM Output: The final binary is a raw Z80 ROM image starting at address 0x0000

This approach provides:

• Fine-grained control over code layout and optimization
• No dependency on external Z80 assembler toolchain
• Easy integration with the Rust ecosystem
• Compile-time code generation with full type safety

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

License

BSD 3-Clause License - see LICENSE for details.

Acknowledgments

• Inspired by MicroPro's WordStar (1978), the first widely-used word processor
• Built on the retroshield-z80-workbench framework
• Designed for the RetroShield Z80 platform by 8-Bit Force

See Also

• RetroShield Z80 Workbench - The code generation framework
• RetroShield Z80 Emulator - Z80 emulator with TUI debugger
• WordStar on Wikipedia - History of the original WordStar