2026-09-01 - (/loop) PPSA21564 boots: the sceLibcMspace allocator family + bcmp

Surveyed the non-PPSA02664 titles for loop-tickable work. PPSA21564 was faulting write to 0x7fff0001 at 131 calls - the Unimplemented placeholder written through as a pointer - and the call right before it was sceLibcMspaceMalloc(0x0, 0x48). The platform's sceLibcMspace* is Doug Lea's mspace arena allocator; unimplemented it answered the placeholder as a 72-byte buffer.

Implemented the family (Malloc/Calloc/Realloc/Free) in orbistoun-libc by delegating to the heap this crate already owns and ignoring the arena handle - sound because the guest only ever touches mspace memory through this same family, so allocate's header and free agree regardless of arena. Also implemented bcmp (= memcmp; equal-vs-not-equal is all it promises), which was called 16k times and, unimplemented, read as "always differ".

Result, repeatable across runs: PPSA21564 went from a 131-call fault to ~550k calls with no fault - it now runs to the call budget instead of crashing. Stub rate 7% -> 4%. Next wants: scePthreadGetthreadid (22.5k calls, needs the thread registry) and a few singletons. Recorded D451. fmt/clippy/tests/knowledge audit pass for the touched crates; the change is additive (new symbols only), so other titles are unaffected.