Re: XYWRITE 4.018 Source Code | request for resources

[Harry Binswanger <dmarc-noreply@xxxxxxxxxxxxx>]

At 08:58 AM 4/3/2026, you wrote:

> Harry, were you able to find the
> NB version of XYWrite that you mentioned earlier? Can you send it my way?
> Thanks.
> Best,
> XYGHOST

No, to my great disappointment.
Regards,
Harry

---

Some of the notes from my current project.

#### Reconstruction Priority Table

| Priority | Seg | Size | XY4% | Language | Strategy |
|----------|-----|------|------|----------|----------|
| 1 | 2,10,26,27,28,59,61,66,67,68 | 1B each | N/A | Stub | `db 0CCh` |
| 2 | 31 | 25B | - | ASM | Disassemble 3 tiny functions |
| 3 | 60 | 24B | - | ASM | Disassemble 1 FAR CALL thunk |
| 4 | 38, 39 | 3,884B | 55% | ASM/Data | `db` tables from XY4 seg021 reference |
| 5 | 36 | 2,149B | 88% | ASM | Bootstrap from XY4 seg021, adapt for Win16 |
| 6 | 64 | 4,303B | 29% | ASM | XY3+XY4 character encoding reference |
| 7 | 58 | 1,435B | 18% | ASM | Small ASM segment with XY4 overlap |
| 8 | 35 | 5,084B | 18% | ASM | XY4 code reference |
| 9 | 3 | 5,543B | 20% | ASM | XY3+XY4 cursor/screen code |
| 10 | All remaining | various | 0-13% | Mixed | Ghidra decompile + fresh disassembly |

### 32. Phase 4 Infrastructure Plan

Three deliverables needed before segment reconstruction can begin:
1. **Stub ASM source files** -- 10 stubs (1 byte each) + seg 31 (25B) + seg 60 (24B)
2. **BUILD_XW.BAT** -- Master build script (assemble all ASM, compile all C, link)
3. **VRFXW.PS1** -- NE-aware segment comparison tool (parse both NE headers, compare per-segment)

### 33. Phase 4 Infrastructure -- CREATED (April 2, 2026)

All three infrastructure deliverables completed:

**Stub ASM source files** (12 files in `BUILD\CORE\`):
- `SEG02.ASM`, `SEG10.ASM`, `SEG26.ASM`, `SEG27.ASM`, `SEG28.ASM` -- 1-byte stubs (LOADONCALL)
- `SEG59.ASM`, `SEG61.ASM` -- 1-byte stubs (LOADONCALL)
- `SEG66.ASM`, `SEG67.ASM`, `SEG68.ASM` -- 1-byte stubs (PRELOAD)
- `SEG31.ASM` -- 25 bytes: CC pad + 4 tiny FAR procs (nullsub, RETF, XOR AX,AX/RETF, STC/RETF)
- `SEG60.ASM` -- 24 bytes: CC pad + FAR CALL to seg42:037Eh + 3x RETF

**Segment naming convention:** `SEGnn_TEXT SEGMENT PARA PUBLIC 'CODE'` for CODE segments.
IDA names them `cseg01`..`cseg72` (CODE) and `dseg73`..`dseg81` (DATA).

**BUILD_XW.BAT**: Master DOSBox build script. Currently assembles stub + small segments.
Link step deferred until more segments are ready. Uses SETENV.BAT for paths.

**VRFXW.PS1**: NE-aware comparison tool. Parses both NE headers, extracts each segment,
compares byte-by-byte. Reports per-segment match/mismatch with offset of first diff.

### 34. Deep Analysis: Seg 36, 38, 39

**Seg 38 & 39** (3,884 bytes each, 0 relocs):
- Structure: ~48-byte header/index, then 2-letter ASCII command codes packed consecutively
- Commands found: CN,SN,SU,UW,US,ET,VL,SZ,FY,OR,WD,FO,PS,PR,LE,PE,PG,HM,CP,FB,FE,UO,GD,PZ,
  YP,XP,XS,GB,GE,B1,B2,BE,AT,EA,EF,PT,PC,VS,?X,FA,FP,NA,GR,PU,F1,F0,DF,CS,JU,DM,DA,SF,SC,
  KH,AC,SE,UC,DL,HY,PP,XB,CO,AO,CR,BX,RD,DI,HV,VU,FU,SK,KS...
- **Seg 38 and 39 are byte-identical** (confirmed). Possible upper/lowercase lookup variants.
- No relocations = pure data, no segment references. Easy reconstruction: raw `db` dump.

**Seg 36** (2,149 bytes, 1 reloc):
- **1 function:** `sub_45A60` (IDA) -- buffer lookup + memory copy routine
  - Entry: PUSH BX/CX/DI/SI/BP, MOV AX,CS / MOV DS,AX (set DS=CS for local data)
  - Searches table at CS:008Bh-00AFh (6-byte entries) for BX match
  - On match: copies 128 bytes with REP MOVSB to SS:3099h (stack segment buffer)
  - Adjusts buffer sizes, calls `sub_542F4` (in another seg) if negative delta
  - Ends: MOV ES, [word_97BD9] (restores ES from global), POP regs, RETF
  - Called from cseg47+AC (`sub_6CAD0`)
- **Data tables** follow the function:
  - 6-byte entries (lookup table at +8Bh to +AFh)
  - Byte sequence 80h-BFh (character mapping table)
  - Sparse data extending to end of segment
- **1 relocation:** The `MOV ES, word_97BD9` at the end references dseg81 (auto data segment)

### 35. First Assembly Build -- SUCCESSFUL (April 2, 2026)

`BUILD_XW.BAT` ran in DOSBox-X. All 12 ASM files assembled with MASM 6.11d:

| File | OBJ Size | Segment | Content |
|------|----------|---------|---------|
| SEG02.OBJ | 73B | SEG02_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG10.OBJ | 73B | SEG10_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG26.OBJ | 73B | SEG26_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG27.OBJ | 73B | SEG27_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG28.OBJ | 73B | SEG28_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG59.OBJ | 73B | SEG59_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG61.OBJ | 73B | SEG61_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG66.OBJ | 73B | SEG66_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG67.OBJ | 73B | SEG67_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG68.OBJ | 73B | SEG68_TEXT 'CODE' | 1-byte stub (0xCC) |
| SEG31.OBJ | 102B | SEG31_TEXT 'CODE' | 25B: 4 tiny FAR procs |
| SEG60.OBJ | 101B | SEG60_TEXT 'CODE' | 24B: FAR CALL thunk |

**OBJ verification:** Hex dump confirms segment names (`SEG02_TEXT`, class `CODE`) and
correct data bytes (e.g., SEG31.OBJ contains `CB CC CB CC 33 C0 CB F9 CB`).

**Bug fixed:** Original `BUILD_XW.BAT` used `for %%F in (...) do (...)` with `%%~nF`
modifiers -- these are Windows CMD features, not available in DOSBox's COMMAND.COM.
Fixed by replacing FOR loops with individual ML commands.

### Phase 4 -- Way Forward

**Segment reconstruction order (81 total segments to build):**

| Priority | Segments | Count | Size | Strategy |
|----------|----------|-------|------|----------|
| **P1 DONE** | 2,10,26,27,28,31,59,60,61,66,67,68 | 12 | 86B | Stub ASM files assembled |
| **P2 NEXT** | 38, 39 | 2 | 7,768B | db dump command tables (0 relocs, pure data) |
| **P3** | 36 | 1 | 2,149B | Bootstrap from XY4 seg021 (88% match, 1 reloc) |
| **P4** | 73-81 | 9 | 206,202B | DATA segments -- db/dw/dd dumps from original |
| **P5** | 63, 57, 41, 23, 33, 58, 56, 40, 43 | 9 | ~20KB | Small ASM/CODE segs (<4KB) |
| **P6** | 35, 64, 3, 5, 8, 21, 30, 48 | 8 | ~36KB | Medium ASM segs with XY4 matches |
| **P7** | 11, 13, 14, 19, 37, 44, 47, 49, 53, 54 | 10 | ~105KB | Larger ASM segs |
| **P8** | 7, 9, 15, 16, 17, 20, 24, 42, 50, 51, 62 | 11 | ~108KB | Mixed C+ASM segs |
| **P9** | 1, 4, 6, 12, 18, 22, 25, 29, 32, 33, 34, 45, 46, 52, 55 | 15 | ~230KB | C compiler-generated segs |
| **P10** | 69, 70, 71, 72 | 4 | 74KB | PRELOAD C segs (entry point, CRT, app init) |