Merge branch 'ppc-audit-fix/p4-abi-truncation' — Phase 4 ABI truncation

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Phase 4 of the PPC instruction audit fix application: 32-bit ABI writeback
truncation across the integer ALU. Six commits + one review-fix land
~43 PPCBUG IDs.

- e18a0a4: 4a active poisoning, NOT/SUB family (006/008/018/019/028/029/030/031/033)
- 145a7a4: 4a/4d coupled extsbx+extshx + CR0 (034+035+036+037)
- bf8208e: 4b immediate ALU (001/002/003/004/005/007)
- 82a9bff: 4b mul/div + srawx coupled (009/010+011/041+042+043)
- 20a730d: 4b halfword + lwa loads (095/096/097/098/105)
- 16993bb: 4c latent + 4d CR0 catch-all (012-017/020/023-026/032/044)
- 49103bb: review-fix — subfx/subfcx OE predicate + mulli test rigor

Independent reviewer caught a blocking issue: subfx/subfcx OE handlers
in batch 6 hadn't been migrated to the inline 32-bit overflow predicate
(`true_diff != (result32 as i32) as i128`), still using the legacy
`sum_overflow_64` which gave spurious OV=1 for any legitimate i32::MIN
result. Fixed in 49103bb with two new discriminating regression tests.

Verification at merge: cargo test --workspace --release reports 494
passed, 0 failed. Acid test deferred to end of all phases per user
direction.

The 32-bit ABI invariant — every GPR write zero-extends from a u32
result, every CR0 update views the result as i32 — is now systematically
restored across the integer ALU. Downstream 64-bit unsigned compares
(the addis-incident shape) can no longer be fed polluted upper bits.

...

This commit is contained in:

MechaCat02

2026-05-02 12:07:53 +02:00

parent f424132a5b 49103bb898

commit d945aeae83

1 changed files with 654 additions and 178 deletions

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crates/xenia-cpu/src/interpreter.rs

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