evv/gw-basic-2026
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Implement VIEW/WINDOW/PALETTE, PMAP, fix MBF float format, update to v0.13.0

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Graphics viewport and coordinate mapping:
- VIEW [[SCREEN] (x1,y1)-(x2,y2) [,[fill][,border]]] with clipping
- WINDOW [[SCREEN] (x1,y1)-(x2,y2)] with Cartesian/screen modes
- PALETTE [attribute, color] with CGA 16-color remapping
- PMAP(coord, func) for logical/physical coordinate conversion
- All graphics statements (PSET, LINE, CIRCLE, PAINT, GET/PUT) respect
  viewport clipping and WINDOW coordinate mapping

MBF (Microsoft Binary Format) float support:
- CVS/CVD now interpret bytes as MBF format (compatible with real GW-BASIC)
- MKS$/MKD$ now produce MBF-encoded bytes
- Fixed shift errors in MBF↔IEEE conversion routines (single: 1→0, double: 4→3)
- Random-access file I/O now byte-compatible with original GWBASIC.EXE

66 tests (2 new), 61 compat matches (up from 58).
This commit is contained in:
Eremey Valetov
2026-03-10 22:20:58 -04:00
parent 4551c88a50
commit 0bacfcef6c
15 changed files with 478 additions and 47 deletions
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README.md
+3 -3
View File
@@ -23,7 +23,7 @@ Interactive mode launches the authentic GW-BASIC full-screen editor:
```
$ ./gwbasic
GW-BASIC 2026 0.12.0
GW-BASIC 2026 0.13.0
(C) Eremey Valetov 2026. MIT License.
Based on Microsoft GW-BASIC assembly source.
Ok
@@ -77,7 +77,7 @@ SPACE$, STRING$, HEX$, OCT$, INSTR, INPUT$
| File management | KILL, NAME, FILES, MKDIR, RMDIR, CHDIR, SHELL |
| Date/time | DATE$, TIME$, TIMER |
| Screen | LOCATE, COLOR, WIDTH, SCREEN, KEY ON/OFF/LIST |
| Graphics | PSET, PRESET, LINE, CIRCLE, DRAW, PAINT, GET/PUT (sprites), BSAVE, BLOAD |
| Graphics | PSET, PRESET, LINE, CIRCLE, DRAW, PAINT, GET/PUT (sprites), BSAVE, BLOAD, VIEW, WINDOW, PALETTE, PMAP |
| Sound | SOUND, BEEP, PLAY (MML) |
| Memory | DEF SEG, PEEK, POKE |
@@ -206,7 +206,7 @@ Source text → Tokenizer (CRUNCH) → Token stream
| Platform | hal_posix.c | OEM*.ASM |
Key design differences from the original:
- IEEE 754 floating point (MBF conversion only for CVI/CVS/CVD compatibility)
- IEEE 754 floating point (MBF conversion for CVI/CVS/CVD/MKI$/MKS$/MKD$ file compatibility)
- Dynamic memory allocation instead of 64KB segment layout
- malloc'd strings instead of compacting garbage collector
- setjmp/longjmp for error recovery