cordle/DOS_BUILD.md

Building Cordle for DOS

Cordle is fully compatible with DOS systems using either DJGPP or Borland C compilers. The code is strictly C90 compliant and includes platform-specific conditional compilation.

Platform Support

Tested Environments

• MS-DOS 6.22
• FreeDOS 1.3
• DOSBox (with DJGPP)
• DOSBox-X

Compiler Options

Option 1: DJGPP (Recommended)

DJGPP is a complete 32-bit C/C++ development system for DOS, based on GCC.

Requirements:

• DJGPP 2.05 or later
• PDCurses library (DOS port)
• GNU Make
• Minimum 2MB RAM

Installation:

1. Download DJGPP from http://www.delorie.com/djgpp/

2. Required packages:

   • djdev205.zip (DJGPP development kit)
   • gcc930b.zip (GNU C Compiler)
   • bnu234b.zip (GNU Binutils)
   • mak43b.zip (GNU Make)

3. Extract all to C:\DJGPP

4. Set environment variables in AUTOEXEC.BAT:

   SET DJGPP=C:\DJGPP\DJGPP.ENV
   SET PATH=C:\DJGPP\BIN;%PATH%
   

Building PDCurses:

1. Download PDCurses from https://pdcurses.org/
2. Extract and build:

   cd pdcurses\dos
   make -f Makefile.dj
   

3. Install:

   copy pdcurses.a C:\DJGPP\LIB\libpdcurses.a
   copy curses.h C:\DJGPP\INCLUDE\
   copy panel.h C:\DJGPP\INCLUDE\
   

Building Cordle:

cd \CORDLE
make

This creates CORDLE.EXE in the build directory.

Option 2: Borland C/C++ 3.1 or Turbo C++

Requirements:

• Borland C/C++ 3.1 or later
• PDCurses for DOS
• Minimum 640KB RAM

Manual Build:

bcc -mc -IC:\BC\INCLUDE -LC:\BC\LIB -std=c90 src\main.c src\game.c src\ui.c src\words.c -lpdcurses -ocordle.exe

Note: Borland uses slightly different command-line syntax. Adjust paths as needed.

File Paths in DOS Build

The DOS version automatically detects the platform and uses DOS-appropriate paths:

DOS Search Order:

1. wordlists\ (relative to executable - for development)
2. C:\CORDLE\wordlists\ (system installation)
3. Custom path via --wordlist argument

Unix Search Order:

1. wordlists/ (relative to executable)
2. /usr/local/share/cordle/wordlists/
3. $HOME/.local/share/cordle/wordlists/
4. Custom path via --wordlist argument

Installation on DOS

Directory Structure

C:\CORDLE\
  ├── CORDLE.EXE
  └── wordlists\
      ├── CORDLE_WORDS_EASY.TXT
      ├── CORDLE_WORDS_MEDIUM.TXT
      ├── CORDLE_WORDS_HARD.TXT
      └── ...

Quick Install

1. Create directory: mkdir C:\CORDLE
2. Copy CORDLE.EXE to C:\CORDLE
3. Copy wordlists directory to C:\CORDLE
4. Add to PATH in AUTOEXEC.BAT:

   SET PATH=C:\CORDLE;%PATH%
   

Running on DOS

C:\> cordle
C:\> cordle --easy
C:\> cordle --medium
C:\> cordle --hard
C:\> cordle --help

Memory Requirements

• Minimum: 2MB RAM (DJGPP), 640KB (Borland)
• Recommended: 4MB RAM
• Display: VGA compatible (for colors)
• DOS Version: 5.0 or higher

Troubleshooting

"Out of memory" Error

• Increase DOS memory limit
• Use CWSDPMI.EXE memory extender (included with DJGPP)
• Free up conventional memory by unloading TSRs

"libpdcurses.a not found"

• Verify PDCurses installation
• Check library path: C:\DJGPP\LIB\

"curses.h not found"

• Copy curses.h to C:\DJGPP\INCLUDE\

Colors Not Working

• Ensure VGA-compatible display
• Try running in DOSBox with machine=svga_s3

Arrow Keys Crash (Fixed in v1.1)

• Arrow keys are now properly handled and ignored
• Update to latest version if experiencing issues

Testing in DOSBox

A DOSBox configuration is included in the dosbox/ directory:

dosbox -conf dosbox/dosbox_config_cordle.ini

Platform Detection

The code automatically detects DOS vs Unix at compile time:

#if defined(__MSDOS__) || defined(_MSDOS) || defined(__DOS__) || defined(MSDOS)
    /* DOS-specific code */
#else
    /* Unix-specific code */
#endif

Differences from Unix Version

1. Curses Library: PDCurses instead of ncurses
2. Path Separators: Backslash (\) instead of forward slash (/)
3. File Paths: DOS-style paths (C:\CORDLE\wordlists\)
4. Executable: .exe extension
5. No HOME Environment: Uses fixed system path instead

Source Code Portability

The code is 100% C90 compliant with:

• No C99/C11 features
• No GNU extensions
• Conditional compilation for platform differences
• Standard library only (stdio, stdlib, string, time, ctype)
• Platform-specific curses handling

For Modern Development

For testing DOS builds on modern systems:

1. Use DOSBox-X (more accurate DOS emulation)
2. Install DJGPP within DOSBox
3. Use cross-compilation from Linux/macOS (advanced)

License Note

Ensure PDCurses license compatibility with your distribution. PDCurses is public domain.

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For Unix/Linux/macOS build instructions, see the main README.md.