0xrsydn/gameboy-rust
1
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

fix(cpu): store PC plus six for Thumb empty register lists

Browse source 
Correct the shared Thumb block-store PC offset from four to six bytes. Retain ARM PC+12, 64-byte empty-list writeback, normal load behavior, alignment, flags, and nominal timing. Correct prior internal expectations and add original regressions for bases, banks, alignment, ROM windows, writeback, clocks, and atomic errors.

The pinned public Thumb ROM now passes its unchanged ARM-state r7 checkpoint after 807 steps and 4170 nominal cycles. The pinned ARM ROM still passes. Neither external ROM nor result assertion is modified.

Validated on Darwin arm64: 848 workspace tests in debug and release; 779 core/demo tests separately; 21 Python adapter tests; both public suites in both profiles; native ROM-window tests; all ten demo window smoke tests; fmt, clippy, rustdoc, and local documentation links.
This commit is contained in:
0xrsydn 2026-10-05 20:47:20 +07:00
commit 3d67b136ba
12 changed files with 222 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

6
docs/rom-tests.md
View file

@ -5,7 +5,7 @@ Each case has a machine-step budget, a completion address, and explicit assertio
A timeout never counts as a pass. Existing `--rom ... --steps ...` remains a diagnostic mode, not a test verdict.
Original programs cover the runner itself. Pinned public [ARM](public-arm-tests.md) and [Thumb](public-thumb-tests.md) ROMs provide independent compatibility results.
The ARM ROM passes its checkpoint. The Thumb ROM currently reports test 229 as failed.
Both pinned ROMs pass their checkpoints on Darwin arm64 in debug and release builds.
Passing the runner's unit tests does not mean an external suite passes.
A passing suite establishes only its specified checkpoints and assertions. It does not establish Emerald compatibility.
@ -133,8 +133,8 @@ They do not hash ROM contents; record source revisions and file checksums alongs
The first public integration is [jsmolka/gba-tests ARM](public-arm-tests.md), with a verified result-register checkpoint.
The pinned ARM ROM now passes this checkpoint on Darwin arm64. Historical failures remain documented.
The [pinned Thumb ROM](public-thumb-tests.md) also has a verified checkpoint, but currently fails its r7 assertion at test 229.
Verify and correct the empty-list store PC value before claiming that suite passes.
The [pinned Thumb ROM](public-thumb-tests.md) also passes its verified r7 checkpoint after the empty-list store correction.
Next, integrate a pinned public memory suite with a verified result protocol.
For further public ARM7TDMI/GBA tests, inspect their source, license, entry assumptions, and result protocol.
Pin source revisions and build instructions before comparing emulator changes.
Adapt suites to verified completion addresses and result locations; do not guess them or treat timeouts as passes.