GE's amMain feedback loop (src/audi.c:531) has a ~3 ms setpoint that PC
scheduling jitter clears, so the SDL queue starves and the device pads
playback with silence -> audio runs permanently ~2 % below real time.
- F5 (the fix): audioGetAiLengthBytes() subtracts a 1024-frame (~46 ms)
cushion before reporting, so the loop tops up while slack remains;
audi.c's control law untouched (rule #2 clean).
- F1: osAiGetLength reports AI_LEN_REG single-buffer semantics (bytes left
in the buffer currently playing), not full SDL queue depth.
- F3: Audio.QueueLimit 8192->2880 + non-silent drops on overflow.
- F4: oversize-block invariant guard.
- GE_D204=1 cheap audio-health monitor (rt/q/drop/max), safe to leave on;
GE_D204_OLD restores pre-fix behaviour for A/B measurement.
Measured A/B in one binary: rt 0.980 -> 1.000, queue min 0 -> 368,
drop 0. Findings: docs/dev/findings.md D204.
Software RSP-audio-ucode mixer (macro-swap aXxx -> Impl functions, PD-port
pattern) makes libaudio output audible on PC. Alongside it, two pointer-width
bugs surfaced by exercising the audio path for the first time:
- D198: alAdpcmPull/_decodeChunk used K0_TO_PHYS (N64 kseg0 mask) on 64-bit
heap pointers; switched to osVirtualToPhysical like every sibling call site.
- D201: bnkf.c bank/inst/sound/wavetable relocation offsets were s32,
truncating the real 64-bit base pointer for ~50% of allocations; widened
to uintptr_t.
- D200 (already committed-pending from a prior session): reverb's ALDelay
u32 negative indices zero-extended into +4GB offsets on 64-bit; (s32)/(s64)
casts match PD ground truth.
- D199: documents the mixer's aSetBuffer persistent-DMEM-context design,
reconstructed from call-site pairs (no RSP disassembly to check against)
since there's no N64 audio ucode source to reference.
- D195/D197 (playtest reports referenced by an earlier HANDOFF note but never
written into findings.md): backfilled as OPEN with next steps.
Verified: ./build-pc.sh ntsc-final links clean; -level_09 runs 600+ frames
crash-free with music + SFX audible.
