Both investigated 2026-09-22 against the MIT PD port fork; neither is v0.4.0
work. Recorded here rather than only in the gitignored notes backlog so the
branch carries the conclusions.
Mod support (D325-D328): community mods repack the ROM, so vanilla offsets are
useless; the fix is an offline importer plus a mod-directory override layer, not
a loader rewrite. GE's file table is in the ROM at 0x252c4 inside the
1172-compressed data segment at 0x21990 (681 exact matches vs filelist, 0
mismatches; hardcode-free discovery reads Random Eye's own table to 704/726
byte-identical). Remaining effort is the mod-dir override layer; added levels
stay blocked by rule 2.
HD texture packs (issue #100): PD's texpack architecture studied - identity, not
decoding, is the problem. Our gfx_pc.cpp is the same lineage and GE_TEXDUMP is
already most of a dumper. Step 1 (address -> texturenum registry) is the only
novel design decision and is a src/game touch needing #ifdef PORT.
Reviewed the PD PC port fork at perfect-dark-dabs-mod-dabs-mod (MIT, same
license as this tree; AGENTS.md already names the PD port a standing reference)
and verified its approach against our own ROM.
Architectural flip: PD does not load a modded ROM. modimport.c states our exact
constraint ('the port cannot run the patched ROM - it runs decomp code and reads
the ROM at fixed offsets') and instead diffs the patched ROM against stock,
extracting what differs into a mod directory its loader already reads. Mod
support is an offline importer plus a file-override layer, not a loader rewrite.
geconvert.c parses a GoldenEye US ROM directly and gives the constants:
DATA_ROM 0x21990, DATA_VRAM 0x80020d90, FILES_AT 0x252c4, 12-byte records with
size by differencing adjacent addresses - exactly obInit.
Verified here: 1172 magic at 0x21990, raw-inflate yields a 247120-byte data
segment (the same inflate port/src/rzdecomp.c already wraps), table at 0x252c4
with 727 rows, and 681 exact offset+size matches against filelist.u.csv with 0
mismatches.
Then reimplemented discovery with NO hardcoded offsets (scan for 1172 in the
first 4 MB, inflate, scan for a >=500-row run counting from 0) and validated on
two real mods by content:
- Random Eye: its own table found at seg 0x219f0 / table 0x25304; 704/726 files
byte-identical to vanilla at the extracted offsets, vs 0/803 at vanilla
offsets in D326. The 22 remainder are fully accounted for: 2 real changes
(UsetupcaveZ, UsetuptraZ), 1 NULLFILE differencing artifact, 19 zero-size
unused bg slots.
- Goldfinger 64 (24 MB): table read correctly, 19/726 identical as expected of a
total conversion.
D327's scans were run over uncompressed ROM bytes, so its mechanism guess was
right and its conclusion wrong; amended here (section heading, inference
paragraph, status line and index row). Also noted: PD's rompatch.c is an MIT
VCDIFF/BPS/IPS decoder, which removes the GPLv2 xdelta3 constraint D325 flagged.
Remaining work is the mod-directory override layer (we have no analogue of PD's
romfile.moddir); rule-2 limit for added levels unchanged. No code changed.
Docs-only. Records the mod-compatibility investigation so it is not re-derived
when mod support is picked up. No code changed.
Measured two shipped community mods against a vanilla NTSC-U ROM:
- Goldfinger 64 v1.0 (12.8 MB xdelta): ROM 12 -> 24 MB, 797/803 vanilla
filelist.u.csv slices differ.
- Random Eye v1.1 (286 KB xdelta): ROM size byte-identical, yet 96.5% of bytes
and 803/803 slices differ; content preserved but shifted (+7216/+7392, one
file -229888).
Both die at tools_pc/d43_emit.py:273 with a zlib error on a slice taken at a
hardcoded vanilla offset. Cause: the file table is compiled in (ob.c ->
file_resource_table.inc.c -> romassets_<region>.s) and the converters reuse the
same vanilla offsets. ROM size is not the constraint; ROM code is never
executed, so ASM hacks are inert regardless.
D325 - Goldfinger 64 probe + mod taxonomy.
D326 - Random Eye repacks too, so D325's hypothesised in-place tier is empty.
D327 - plan settled: reading the table from the ROM is ruled out by measurement
(hw_address absent in all four encodings tested, 0 hits for the
segment-relative form; two structural fileentry scans found nothing);
content-addressed offset remapping with gap inference is the viable route,
since obInit differencing proves files are contiguous.
Also recorded: GE maps its 0x7F000000 game segment directly from ROM,
uncompressed, uniquely signature-findable at ROM 0x34b30.
The 1964GEPD fork reviewed in D327 is GPL-2.0 against this MIT tree; no code
was copied or vendored, facts re-derived from our own ROM and decomp.
James Dansereau