* [cpu] Implement SysV variadic float ABI (xmm0-7 capture, float returns, printf %f)
The import trampoline spilled only xmm0 and never reloaded a return xmm0. The
guest uses the System V AMD64 ABI: variadic float args pass in xmm0..xmm7 and
float/double returns come back in xmm0. As a result variadic float args past
the first were unavailable to HLE handlers, float returns never reached the
guest, and direct printf read %f/%e/%g from GP registers instead of XMM,
printing garbage and desynchronizing every following argument.
- Trampoline: spill xmm0..xmm7 into a 0x80-byte save area below the GP argpack
(r12 stays at the argpack base) and reload the return xmm0 in the epilogue.
- Gateway: read xmm0..7 from the save area into CpuContext and write the
handler's xmm0 back. XMM is caller-saved in SysV, so restoring xmm0 on return
is safe for non-float imports too.
- RegisterPrintfArgumentSource: read float args from xmm0..7 with independent
GP/FP counters and a shared stack-overflow cursor.
Every emitted byte was decoded; a unit test confirms float args read xmm0..7
(not GP) and interleaved "%d %f %d %f" stays synchronized. Build 0/0.
* [cpu] Document the scalar-only leaf-import constraint at its registration site
- IsLeafImport: spell out the no-XMM-args / no-XMM-return invariant the fast
path relies on and what breaks if it is violated; record the 2026-07-11 audit.
- Name every previously uncommented NID in the leaf list (mutex lock/unlock,
usleep, the Ampr/Apr command-buffer block, the unknown AGC packet NID).
- IsNoBlockLeafImport: document that it is a sub-filter of IsLeafImport and
that its five extra entries currently take the full gateway path; fix the
mislabeled K-jXhbt2gn4 comment (pthread_mutex_trylock, not
scePthreadMutexTrylock, which is upoVrzMHFeE).
- Point the DispatchImport call-site note at the audited list.
Comment-only change: the comment-stripped diff is empty and the solution
builds with 0 warnings / 0 errors.
f43f7cde9c