Eremey Valetov
c488cb526d
Expand roadmap with detailed implementation plans for the next three features: MBF binary file compatibility (token-stream conversion at load/save boundary), hardware I/O simulator (portio.c with PIT/speaker/ CGA/joystick port emulation), and DRAW command fixes (M parsing bug, scale semantics, A rotation, TA/variable substitution). Remove hardware I/O from known limitations (moving to planned). Fix stale test counts (64 -> 66) and version string (0.11.0 -> 0.13.0) across docs.
101 lines
4.6 KiB
Markdown
101 lines
4.6 KiB
Markdown
# Roadmap
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## The Big One
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- **GW-BASIC 2026 Compiler** — ahead-of-time compilation of BASIC programs to
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native executables. Because nothing says "premature optimization" like
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compiling a language designed for an interpreter running on a 4.77 MHz 8088.
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But we've come this far, so why not? Likely approach: translate the token
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stream to C and lean on GCC/Clang for the heavy lifting.
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## Next Up (v0.14.0)
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### MBF Binary File Compatibility
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Make the binary tokenized file format fully compatible with original GWBASIC.EXE
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files. Currently, float constants in the token stream are stored as IEEE 754;
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the original uses Microsoft Binary Format (MBF).
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**Approach:** always store MBF on disk, always IEEE in memory. Convert at the
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`load_binary()`/`save_binary()` boundary in `program_io.c`. A token-walking
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function scans each line for `TOK_CONST_SNG` (0x1C, 4 bytes) and
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`TOK_CONST_DBL` (0x1F, 8 bytes) and converts in-place using the existing
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`gw_mbf_to_ieee_*` / `gw_ieee_to_mbf_*` routines. The walker must skip string
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literals, REM/DATA regions, and multi-byte tokens to avoid false positives.
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This makes round-tripping lossless (MBF single has the same 24-bit mantissa as
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IEEE single; MBF double's 56 bits cleanly contain IEEE double's 53 bits) and
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enables loading authentic `.BAS` files from the 1980s.
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### Hardware I/O Simulator
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An optional emulation layer for `OUT`, `INP`, `WAIT`, `MOTOR`, and friends,
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following the established `virmem.c` dispatch-by-address pattern.
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**New module:** `portio.c` / `portio.h` with `portio_inp(port)` /
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`portio_out(port, value)` dispatch.
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**Priority ports:**
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| Port | Device | Emulation |
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|------|--------|-----------|
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| 0x42–0x43 | 8253 PIT channel 2 | Speaker frequency divisor (1193180 / divisor Hz) |
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| 0x61 | PPI Port B | Speaker on/off (bits 0–1), routes to `snd_start_continuous()` / `snd_stop_continuous()` |
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| 0x3D8 | CGA mode control | Mode register storage, feeds `gfx_init()` |
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| 0x3D9 | CGA color select | Palette/background bits, feeds `gfx_palette_set()` |
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| 0x201 | Game port | Joystick stub (returns 0xF0 = no buttons) |
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| 0x3F8–0x3FE | COM1 serial | Minimal stub (LSR reports transmitter ready to prevent spin loops) |
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| Default | — | Reads return 0xFF (floating bus), writes silently discarded |
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**Statement/function changes:**
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- `OUT port, value` → `portio_out(port, value)`
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- `WAIT port, mask [, xor_mask]` → busy loop with `portio_inp()`, break check, timeout
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- `MOTOR` → accept and silently ignore
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- `INP(port)` → `portio_inp(port)` (currently returns 0)
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- `STICK(n)` / `STRIG(n)` → joystick state from port 0x201
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### DRAW Command Fixes
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The DRAW mini-language parser has three bugs and four missing features.
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**Bugs to fix:**
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1. **M command parsing** — the generic argument parser consumes digits that
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belong to M's x-coordinate, so `DRAW "M100,50"` moves to (0, 50). Fix:
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skip the generic parser when the command is M.
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2. **S (scale) semantics** — scale is used as a default distance instead of a
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multiplier. `DRAW "U"` moves 4 pixels instead of 1. Correct formula:
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`dist = (has_arg ? arg : 1) * scale / 4`.
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3. **A (90° rotation)** — recognized but no-op. Needs a rotation state
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variable and direction vector transform for U/D/L/R/E/F/G/H.
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**Features to add:**
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- `TA n` — arbitrary rotation angle (degrees, −360 to 360); requires
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multi-character command parsing and trigonometric direction vector rotation
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- `=variable;` — numeric variable substitution in DRAW strings; requires
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passing variable lookup capability into `gfx_draw()`
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- `X subexpr;` — execute sub-string from a string variable (recursive parse)
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- Scale applied to relative M coordinates
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## IDE and Notebook Integration
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- **Jupyter kernel for GW-BASIC** — a Jupyter Notebook kernel that runs
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GW-BASIC programs cell-by-cell, with rich output for `PRINT`, inline graphics
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rendering for drawing commands, and interactive `INPUT` via notebook widgets.
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Similar in spirit to [foxkernel](https://github.com/evvaletov/foxkernel).
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- **JetBrains plugin (IntelliJ/CLion)** — full-featured language plugin with
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syntax highlighting, code completion, line number navigation, run
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configurations, debugger integration (breakpoints via `STOP`, variable
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inspection), structure view (line number outline), and error annotations.
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- **VS Code extension** — language extension providing syntax highlighting
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(TextMate grammar), snippets, run/debug tasks, integrated terminal runner,
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and Language Server Protocol support for diagnostics and hover info.
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## Known Limitations
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- String garbage collection not implemented (uses `malloc`/`free` instead)
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- Maximum 256 variables, 64 arrays, 16 FOR nesting, 24 GOSUB nesting,
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16 WHILE nesting
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