New Makefile.dos16 builds with OpenWatcom wcc (16-bit, MEDIUM model)
producing a standard MZ executable that runs on any DOS without DOS/4GW.
All 24 source files compile clean; tested on FreeDOS 1.4 via QEMU.
Changes for 16-bit compatibility:
- hal_dos.c: INTX macro selects int86() vs int386() based on _M_I86
- sound.c: reduce stack buffer from 8192 to 512 samples on 16-bit
- tui.c: gracefully disable TUI if screen buffer allocation fails
(near heap exhaustion common on 16-bit), batch mode still works
- .gitignore: add .obj/.exe/.err/.lib for OpenWatcom build artifacts
Size comparison:
- 32-bit DOS/4GW: 175KB + 265KB extender = 440KB total
- 16-bit real-mode: 127KB standalone
The 32-bit build (Makefile.dos) and Linux build are unaffected.
72/72 interpreter tests pass.
All 24 source files compile and link for DOS/4GW 32-bit target using
OpenWatcom V2 cross-compiler (wcc386 -bt=dos -mf -za99 -D__MSDOS__).
Platform portability fixes:
- hal_dos.c: use int386() instead of int86() for 32-bit DOS
- interp.c: mkdir() 1-arg on DOS, _dos_findfirst/findnext for FILES,
monotonic_time() portable wrapper for clock_gettime/clock()
- virmem.c: replace clock_gettime with portable time()/localtime()
- graphics.c: define M_PI, avoid non-constant aggregate initializers
- tui.c: guard sys/ioctl.h and sigaction, use signal() on DOS,
use HAL screen size instead of TIOCGWINSZ
Produces: gwbasic.exe (154KB LE executable, requires DOS4GW.EXE)
Linux build and all 72+14+69 tests unaffected.
platform/hal_dos.c: DOS HAL implementation using BIOS INT 10h for
screen/cursor, INT 16h for keyboard, direct character output via
BIOS write-char. Compile-time selection via __MSDOS__ define.
Linux HAL (hal_posix.c) unchanged -- full backward compatibility.
hal.h: add hal_dos_create() declaration under __MSDOS__ guard.
main.c, gwrt.c: select HAL at compile time via #ifdef __MSDOS__.
Makefile.dos: OpenWatcom wmake build file targeting DOS/4GW 32-bit.
Builds GWBASIC.EXE (interpreter), GWBASCOM.EXE (compiler),
GWRT.LIB (runtime library for compiled programs).
All 72 interpreter, 14 kernel, and 69 compiler tests continue to
pass on Linux (no regression).
Add GitHub Actions CI with automated build and test. Implement real
terminal I/O with raw mode (enable_raw/disable_raw, proper INKEY$
polling via VMIN=0/VTIME=0, INPUT$ function). Add Sixel graphics
engine with virtual framebuffer (SCREEN 1: 320x200, SCREEN 2:
640x200), Bresenham line drawing, midpoint circle, flood fill PAINT,
DRAW mini-language parser, and Sixel encoder with RLE. Replace all
graphics stubs with real implementations (PSET, LINE, CIRCLE, DRAW,
PAINT, COLOR, SCREEN, POINT). Fix AND/OR/XOR operator precedence
to be lower than relational operators. Add 13 classic test programs
(39 total). Bump version to 0.5.0.
GW-BASIC reimplementation in C11, using Microsoft's open-sourced 8088
assembly as the authoritative reference.
Tokenizer (CRUNCH/LIST), expression evaluator with operator precedence,
all math functions (SIN, COS, TAN, ATN, SQR, LOG, EXP, RND, etc.),
string functions (LEFT$, RIGHT$, MID$, CHR$, ASC, VAL, STR$, etc.),
PRINT statement with comma/semicolon zones, TAB(), SPC().
Handles integer/single/double types with correct promotion, D exponent
for double-precision literals, type suffixes (%, !, #), &H hex/&O octal
literals, MBF conversion routines, and GW-BASIC-compatible number
formatting.
Platform-independent via HAL vtable; POSIX backend included.
Eremey Valetov
Eremey Valetov