BUILD.md

Build from sources (In Progress)

Environment

• Target platform: DOS
• Compiler (C/C++): "Watcom C/C++ Compiler 10.5"
• Compiler (ASM): Borland Turbo Assembler 5 (or simply TASM5)
• DOS/4G extender which is included with the Watcom C compiler (as DOS/4GW)

Prepare environment

• Target OS: DOSBox 0.74, an open source DOS emulator for BeOS, Linux, Mac OS X, OS/2, and Windows.
• Compiler for C/C++: Open Watcom C/C++ 1.9 or Open Watcom C/C++ 2.0

macOS

Run DOSBox

Install DOSBox.app to /Applications directory.

Assume that the root folder for experiments is /Volumes/Development/Games/Doom2D

Create "C:"-drive directory on the host OS.
mkdir -p /Volumes/Development/Games/Doom2D/develop_drive

Create DOSBox configuration file /Volumes/Development/Games/Doom2D/develop.conf with content:

[dos]
xms=true
ems=true
umb=true
keyboardlayout=866

[autoexec]
@ECHO OFF
MOUNT C "/Volumes/Development/Games/Doom2D/develop_drive" -freesize 1024
C:

See DOSBox wiki about MOUNT command

Run DOSBox with config.
open -a DOSBox --args -conf /Volumes/Development/Games/Doom2D/develop.conf

Install Open Watcom compiler

Download Open Watcom C/C++ compiler 1.9 for DOS
On host-machine:
\curl -SL -O ftp://ftp.openwatcom.org/install/open-watcom-c-dos-1.9.exe -o /Volumes/Development/Games/Doom2D/develop_drive/wc_1_9.exe
On guest-machine:

> C:
> WC_1_9.EXE

Choose Full installation.
Choose Let you make the modifications later.
Choose Create file for CONFIG.SYS and for AUTOEXEC.BAT (installer has a bug, you must choose this option).

Remove CONFIG.SYS and AUTOEXEC.BAT files as unused:

> DEL CONFIG.SYS
> DEL AUTOEXEC.BAT

Copy /Volumes/Development/Games/Doom2D/develop_drive/WATCOM/AUTOEXEC.DOS content to [autoexec] section of develop.conf file right between MOUNT C ... and C: lines.

Known problems

Buggy encoding in DOSBox or Watcom compiler, or pair.

See also

32bit DOS Development with Open Watcom Tutorial: How to compile pcasm example codes on DosBox