Files
psxrecomp/runtime/include
Matthew Stanley 8b0fc34714 phase4: SELECT-deassert protocol reset + slot-state instrumentation
Real card protocol restarts on every fresh 0x81 — SELECT deassert is
a bus-wide reset signal. Earlier model preserved mc_state across
deassert via mc_save_slot, which caused every subsequent 0x81 to land
on a stale non-IDLE saved state and trigger abort_reselect bookkeeping.
Audit confirmed the BIOS-visible RX was still correct (the abort path
itself reset mc_state), but the retained sector/cmd/counter context
across logically-independent transactions was wrong per no$psx.

Clear volatile protocol state on SELECT deassert (state, cmd, sector,
sector_msb, sector_lsb, data_idx, checksum on both slots). Preserve
mc_slots[].flag (persistent "new card" metadata) and mc_slots[].data
(sector buffer, harmless to retain).

Result on a 4-press boot run: 6 transactions reach READ_DATA (ts=10)
and successfully read the "MC" header magic (RX bytes 0x4D 0x43);
remaining txns continue as 4-byte presence pings. Pre-fix: 0 reads
of card data ever; post-fix: card protocol can complete the setup
phase and enter data phase.

The byte-15 abort that follows is a separate blocker — kernel chain
dispatcher interleaves pad polling into the card data read. Tracked
for next session via the chain dispatcher disassembly.

Also includes:
- Slot-state capture in SioTraceEntry + sio_trace JSON emission
- dirty_ram_interp: replace mid-block fprintf+fflush with a counter
  (CLAUDE.md §3 — synchronous Windows console I/O at high rate
  starves the dispatch loop)
- Passive Python TCP probes (raw_tcp, trace_audit, trace_range,
  txn_summary, txn_dist, txn_bytes, drs_filter, readram_test,
  step_audit{,2}, verify_card_buffer, wtrace_filter)
- docs/MEMCARD_AUDIT_2026_04_28.md (prior session's 7-layer audit)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-29 14:46:26 -07:00
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