Update Sphinx docs with v0.14.0 roadmap and fix stale references

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.

docs/architecture.md

@@ -57,7 +57,7 @@ HAL writes straight to stdout.
 src/         — core interpreter (21 files)
 include/     — headers (13 files)
 platform/    — HAL backends (1 file)
-tests/       — 64 automated test programs, 4 classic interactive programs, compat harness
+tests/       — 66 automated test programs, 4 classic interactive programs, compat harness
 docs/        — Sphinx documentation
 ```
 

docs/getting-started.md

@@ -37,7 +37,7 @@ Running `./gwbasic` with no arguments launches the full-screen editor:
 
 ```
 $ ./gwbasic
-GW-BASIC 2026 0.11.0
+GW-BASIC 2026 0.13.0
 (C) Eremey Valetov 2026. MIT License.
 Based on Microsoft GW-BASIC assembly source.
 Ok

docs/index.md

@@ -24,7 +24,7 @@ version is structured as modular C suitable for new feature development.
 - **Printer output** — `LPRINT`/`LLIST` to file or real hardware via `--lpt`
 - **Classic programs** — Hamurabi, Lunar Lander, Gunner, and Diamond from
   David Ahl's *BASIC Computer Games* (1978) run out of the box
-- **64 test programs** with golden-file regression testing and DOSBox-X
+- **66 test programs** with golden-file regression testing and DOSBox-X
   compatibility testing against real GWBASIC.EXE
 - **MIT License**
 

docs/roadmap.md

@@ -8,15 +8,76 @@
   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.
 
-## Planned Features
+## Next Up (v0.14.0)
 
-- **Hardware I/O simulator** — an optional emulation layer for `OUT`, `INP`,
-  `WAIT`, `MOTOR`, and friends.  The idea is to provide a virtual PC peripheral
-  bus so retro programs that talk to the speaker, joystick port, or parallel
-  interface can do *something* useful instead of silently no-oping.  Think of it
-  as a tiny museum exhibit for vintage BASIC hardware hacking.
-- **MBF format support for binary LOAD** — convert Microsoft Binary Format
-  float constants when loading files saved by the original GWBASIC.EXE
+### MBF Binary File Compatibility
+
+Make the binary tokenized file format fully compatible with original GWBASIC.EXE
+files.  Currently, float constants in the token stream are stored as IEEE 754;
+the original uses Microsoft Binary Format (MBF).
+
+**Approach:** always store MBF on disk, always IEEE in memory.  Convert at the
+`load_binary()`/`save_binary()` boundary in `program_io.c`.  A token-walking
+function scans each line for `TOK_CONST_SNG` (0x1C, 4 bytes) and
+`TOK_CONST_DBL` (0x1F, 8 bytes) and converts in-place using the existing
+`gw_mbf_to_ieee_*` / `gw_ieee_to_mbf_*` routines.  The walker must skip string
+literals, REM/DATA regions, and multi-byte tokens to avoid false positives.
+
+This makes round-tripping lossless (MBF single has the same 24-bit mantissa as
+IEEE single; MBF double's 56 bits cleanly contain IEEE double's 53 bits) and
+enables loading authentic `.BAS` files from the 1980s.
+
+### 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 with `portio_inp()`, break check, timeout
+- `MOTOR` → accept and silently ignore
+- `INP(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:**
+
+1. **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.
+2. **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`.
+3. **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 into `gfx_draw()`
+- `X subexpr;` — execute sub-string from a string variable (recursive parse)
+- Scale applied to relative M coordinates
 
 ## IDE and Notebook Integration
 
@@ -37,4 +98,3 @@
 - String garbage collection not implemented (uses `malloc`/`free` instead)
 - Maximum 256 variables, 64 arrays, 16 FOR nesting, 24 GOSUB nesting,
   16 WHILE nesting
-- Hardware I/O (`OUT`, `INP`, `WAIT`, `COM`, `MOTOR`) not yet implemented