Lua for Open Watcom

This repository contains wmake style makefiles and patches to build Lua on Open Watcom 1.9 or later. The primary goal was to allow Lua scripts to be run on DOS systems in real mode but has expanded to include all Open Watcom targets that don't require external dependencies to build.

Download

Pre-compiled builds are available on the Release page.

Files

There are two zips available for download in each release. Which one you should download depends on how you plan to use the software. Both zips contain binaries for all listed platforms. See Binary Native Targets and Binary Compatibility Matrix to determine which binary is right for your system.

Lua Exe.zip

This zip contains all demo scripts and platform binaries as regular files. The zip is formatted with DOS headers and has 8.3 friendly names.

Lua Ima.zip

This zip contains two floppy disk format images (.ima format) which are ready to be written to real disks for distributing to retro machines or opened by emulators directly. To save space on these disk images binaries have been compressed by UPX where possible.

Disk Image	Description
LUAMULTI.IMA	A 1.4MB 3½ floppy disk image that contains all the same files as Lua Exe.zip
LUA160k.IMA	A 160k 5¼ floppy disk image with subset of scripts with only the DOS binary due to space limitations of this type of disk

System Requirements

Lua for Watcom binaries can run on a number of legacy systems as well as some modern ones. The exact memory requirements will depend on the complexity of the script you want to run.

Binary Native Targets

Since Open Watcom can produce binaries for several operating systems, each binary has been given a unique name to distinguish the native Operating System (OS) and Instruction Set Architecture (ISA) it is intended for.

Binary Name	Native OS	Native ISA
LUA16.EXE	Real mode DOS	8086
LUA21.EXE	OS/2 1.2	80286
LUA22.EXE	OS/2 2.0	80386
LUA4G.EXE	DOS4GW extender	80386
LUANT.EXE	Windows 95	80386

Binary Compatibility Matrix

Some OSes can run binaries intended for another out of the box. Do keep in mind, however, that in most of these cases the OS is newer and has higher minimum requirements.

Operating System	Minimum OS ISA(s)	LUA16.EXE	LUA21.EXE	LUA22.EXE	LUA4G.EXE	LUANT.EXE
DOS 2.x - 4.x Windows 1.x - 3.x	8086	Yes	No	No	No	No
DOS 5.x - 7.x	8086 80386SX	Yes	No	No	No Yes	No
OS2 1.0 - 1.1	80286	Yes	No	No	No	No
OS2 1.2 - 1.3	80286	Yes	Yes	No	No	No
OS2 2.x	80386SX	Yes	Yes	Yes	No	No
OS2 3.x	80386SX	Yes	Yes	Yes	Yes	No
OS2 4.x	80486SX	Yes	Yes	Yes	Yes	No
Windows 95	80386SX	Yes	No	No	Yes	Yes
Windows 98	80486DX 80486SX+80487SX	Yes	No	No	Yes	Yes
Windows 2000 - ME	80586	No	No	No	No	Yes
Windows XP	80586 x86_64	No	No	No	No	Yes
Windows Vista - 10	80686 x86_64	No	No	No	No	Yes
Windows 11	x86_64	No	No	No	No	Yes

Build System Requirements

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

Build Requirement	Sources
Lua 5.4 source code (or git submodules)	lua.org (GitHub)
Open Watcom 1.9 (or later)	openwatcom.org
Operating System supported by Open Watcom (at least MS-DOS 5.0)	FreeDOS, SvarDOS and/or an emulator
80386 compatible processor	AMD/Intel processor made after 2008 or an emulator
A patching utility	GNU Patch or DifPat

If in doubt, an emulator can be used to run the DOS version of Open Watcom on a modern machine

How to build

1. Extract Luas source code to the Lua folder. This can be achieved in two ways:

   • Use git submodules init then git submodules update --recursive to get the sources directly from the Lua mirror repository
   • Download the Lua 5.4.x sources tarballs from https://lua.org/ftp/, extract them and copy all files in src to Lua

2. Patch the source code for Watcom (optional):

   GNU Patch	DifPat
   patch -p0 -i lua.pat	pat lua.pat .

   If no patching program is available mimic the changes in each .pat file manually. Patch changes are minimal and only serve to silence Watcom compiler warnings

3. Build Lua with the following commands:

   Make Command	Binary File	Target OS	Target ISA
   wmake -f wm_dos16.mak	dist/bin/lua16.exe	PC-DOS 2.0+	8086 or later
   wmake -f wm_dos4g.mak	dist/bin/lua4g.exe	MS-DOS 5.0+	80386 or later
   wmake -f wm_os216.mak	dist/bin/lua21.exe	OS/2 1.2	80286 or later
   wmake -f wm_os232.mak	dist/bin/lua22.exe	OS/2 2.0	80386 or later
   wmake -f wm_winnt.mak	dist/bin/luant.exe	Windows 95+	80386 or later

See also

Emulators

If you do not have retro hardware but want to try Lua for Watcom any of the following emulators can be used to run the Lua binaries from a modern machine.

Emulator	Emulation Type	Repository	Comment
86Box	PC Hardware	https://github.com/86Box/86Box	Requires firmware blobs. For best experience use with 86Box launcher
DOSBox-X	DOS Software	https://github.com/joncampbell123/dosbox-x	Not to be confused with DOSBox
PCem	PC Hardware	https://github.com/sarah-walker-pcem/pcem/	Requires firmware blobs.
Qemu	Hypervisor	https://gitlab.com/qemu-project/qemu	Often used with libvirt. Only recommended for guests with driver support (Windows XP and later)

Other software

Retro computer enthusiasts may be interested in Lua for ELKS (and ELKS in general).