Lua for Open Watcom

This repository contains wmake style makefiles an patches to build Lua 5.4.6 on Open Watcom 1.9 or later. The primary goal for these is to allow Lua scripts to be run on DOS systems in real mode.

Runtime Requirements

To run Lua built by Open Watcom you will need the following:

Requirement	Sources/Comment
8088 CPU* *or compatibiles like the 8086, V20, 286, 386 etc Machine emulators provided as an option for other ISAs	86Box (GitHub) DOSBox-X (GitHub) PCem (GitHub)
PC-DOS 2.1 or higher	FreeDOS DOSBox-X (GitHub) SvarDOS
At least 320 kilobytes of total system memory	Any memory above 640 kilobytes is inaccessible to all real mode DOS programs
At least 600 kilobytes of hard disk space or x2 360 kilobyte diskettes	Can be ran directly from a diskette on machines without a hard drive

If in doubt, install DOSBox-X

Build Requirements

To build Lua with Open Watcom you will need the following:

Requirement	Sources
Lua 5.4.6 source code	lua.org (GitHub)
Open Watcom 1.9 (or later)	openwatcom.org (GitHub) FreeDOS Bonus CD (FDIMPLES) SvarDOS (PKGNET repository)
DOS operating system (MS-DOS 5.0 compatible)	FreeDOS DOSBox-X (GitHub) SvarDOS
80386 compatible processor* *Any AMD or Intel CPU made in the last 3 decades is compatible. Machine emulators provided as an option for other ISAs	86Box (GitHub) DOSBox-X (GitHub) PCem (GitHub) Qemu (GitLab)
A patching utility	GNU Patch DifPat

If in doubt, install DOSBox-X

How to build

1. Extract Luas source code
2. Copy all files in this repository to the src folder of the extracted content
3. Patch the source code for Watcom:

GNU Patch	DifPat
patch luaconf.h luaconf.pat	pat luaconf.pat luaconf.h
patch lopcodes.h lopcodes.pat	pat lopcodes.pat lopcodes.h
patch lutf8lib.c lutf8lib.pat	pat lutf8lib.pat lutf8lib.c

If no patching program is available mimic the changes in each .pat file manually. Patch changes are minimal

4. Build Lua for real mode DOS with wmake -f watcom_l.mak
   • If successful dist/bin/dos16.exe and dist/bin/dosc16.exe will be created
5. Clean up object files with wmake -f watcom_l.mak clean
6. Build Lua for DOS4GW with wmake -f watcom_f.mak
   • If successful dist/bin/dos4g.exe and dist/bin/dosc4g.exe will be created
7. Clean up object files with wmake -f watcom_f.mak clean

Other targets may work but are untested