Eremey Valetov
3f3104c385
Binary tokenized SAVE/LOAD now stores float constants in Microsoft Binary Format (MBF) on disk, matching original GWBASIC.EXE. A token-walking function (convert_floats) converts IEEE↔MBF at the save_binary()/load_binary() boundary. Also fixes a latent bug where load_binary() scanned for 0x00 to find the end of each token line — this fails when float bytes contain null (e.g. MBF for 100.5 is 00 00 49 87). The loader now uses the next-line pointer to compute token data length, matching the original's approach.
3.8 KiB
3.8 KiB
Roadmap
The Big One
- GW-BASIC 2026 Compiler — ahead-of-time compilation of BASIC programs to native executables. Because nothing says "premature optimization" like compiling a language designed for an interpreter running on a 4.77 MHz 8088. But we've come this far, so why not? Likely approach: translate the token stream to C and lean on GCC/Clang for the heavy lifting.
Next Up (v0.14.0)
Hardware I/O Simulator
An optional emulation layer for OUT, INP, WAIT, MOTOR, and friends,
following the established virmem.c dispatch-by-address pattern.
New module: portio.c / portio.h with portio_inp(port) /
portio_out(port, value) dispatch.
Priority ports:
| Port | Device | Emulation |
|---|---|---|
| 0x42–0x43 | 8253 PIT channel 2 | Speaker frequency divisor (1193180 / divisor Hz) |
| 0x61 | PPI Port B | Speaker on/off (bits 0–1), routes to snd_start_continuous() / snd_stop_continuous() |
| 0x3D8 | CGA mode control | Mode register storage, feeds gfx_init() |
| 0x3D9 | CGA color select | Palette/background bits, feeds gfx_palette_set() |
| 0x201 | Game port | Joystick stub (returns 0xF0 = no buttons) |
| 0x3F8–0x3FE | COM1 serial | Minimal stub (LSR reports transmitter ready to prevent spin loops) |
| Default | — | Reads return 0xFF (floating bus), writes silently discarded |
Statement/function changes:
OUT port, value→portio_out(port, value)WAIT port, mask [, xor_mask]→ busy loop withportio_inp(), break check, timeoutMOTOR→ accept and silently ignoreINP(port)→portio_inp(port)(currently returns 0)STICK(n)/STRIG(n)→ joystick state from port 0x201
DRAW Command Fixes
The DRAW mini-language parser has three bugs and four missing features.
Bugs to fix:
- M command parsing — the generic argument parser consumes digits that
belong to M's x-coordinate, so
DRAW "M100,50"moves to (0, 50). Fix: skip the generic parser when the command is M. - S (scale) semantics — scale is used as a default distance instead of a
multiplier.
DRAW "U"moves 4 pixels instead of 1. Correct formula:dist = (has_arg ? arg : 1) * scale / 4. - A (90° rotation) — recognized but no-op. Needs a rotation state variable and direction vector transform for U/D/L/R/E/F/G/H.
Features to add:
TA n— arbitrary rotation angle (degrees, −360 to 360); requires multi-character command parsing and trigonometric direction vector rotation=variable;— numeric variable substitution in DRAW strings; requires passing variable lookup capability intogfx_draw()X subexpr;— execute sub-string from a string variable (recursive parse)- Scale applied to relative M coordinates
IDE and Notebook Integration
- Jupyter kernel for GW-BASIC — a Jupyter Notebook kernel that runs
GW-BASIC programs cell-by-cell, with rich output for
PRINT, inline graphics rendering for drawing commands, and interactiveINPUTvia notebook widgets. Similar in spirit to foxkernel. - JetBrains plugin (IntelliJ/CLion) — full-featured language plugin with
syntax highlighting, code completion, line number navigation, run
configurations, debugger integration (breakpoints via
STOP, variable inspection), structure view (line number outline), and error annotations. - VS Code extension — language extension providing syntax highlighting (TextMate grammar), snippets, run/debug tasks, integrated terminal runner, and Language Server Protocol support for diagnostics and hover info.
Known Limitations
- String garbage collection not implemented (uses
malloc/freeinstead) - Maximum 256 variables, 64 arrays, 16 FOR nesting, 24 GOSUB nesting, 16 WHILE nesting