Implements M4: memory_manager.v (arbitration/buffering/forwarding/ latency hiding/double buffering, §12) + prefetch_engine.v (double-buffered tile fetch, §13), sitting on the REAL, UNMODIFIED V1 PSRAM backend chain (int8_memory_access.v -> memory_interface.v -> psram_controller.v, per §15's explicit mandate not to touch the controller). Verified fully end-to-end with Verilator: real neural_processor (M1) fed entirely by memory_manager, computing against PSRAM-resident X/W tiles (double-buffered prefetch across up to 5 tiles) and writing its result back to PSRAM -- checked via an independent PSRAM read-back, with poison bytes around the operand regions to catch addressing errors. 3/3 jobs pass (1/3/5-tile configurations). Three real RTL bugs found and fixed during integration (full diagnostic trail in errors.log ERR-0006): prefetch_engine had no single-in-flight-request discipline, letting a queued request corrupt the bank bookkeeping of a fetch already running; the fix's own !pf_busy guard had a one-cycle blind spot (pf_busy lags pf_start by a clock) that needed an explicit !pf_start term; and a state-based mux for the shared backend port was off by one cycle, silently dropping the PSRAM result write entirely. Real synthesis: 0 CHECK problems, 851 LUT4/789 FF/108 CCU2C/0 DSP (expected, no multiplication in this module). Real place&route (via a synthesis-only timing harness, needed for the same TRELLIS_IO pin- budget reason as M2's array): Fmax 165.86 MHz, PASS at 80MHz. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
Formato dei log V2
Regola non negoziabile (docs/v2-description.md §25-29): ogni attività
significativa (modifica, simulazione, sintesi, benchmark, decisione, errore)
deve essere registrata. Nessun log viene mai sovrascritto o troncato — solo
append. Nessun ID esperimento (EXP-XXXX) o decisione (DEC-XXXX) viene mai
riutilizzato, anche se il risultato è un FAIL.
File
development.log— log principale di sviluppo, un'entry per ogni sessione di lavoro/milestone (creazione file, refactor, avanzamento roadmap).architecture.log— decisioni e note di architettura a grana fine (non scelte finali — quelle vanno indecisions.log— ma esplorazioni, alternative considerate, vincoli scoperti).simulation.log— ogni run di simulazione (Icarus/Verilator): test, vettori, cicli, PASS/FAIL, confronto bit-exact con V1, stall/memory-wait.synthesis.log— ogni run Yosys: LUT/FF/DSP/BRAM, warning, problemi CHECK.timing.log— ogni run nextpnr-ecp5: Fmax, percorso critico, WNS/TNS se disponibili. Fmax "ufficiale" di una configurazione = solo da qui, mai da simulazione o stima.benchmark.log— tabelle di confronto per configurazione (Fmax, MAC/cycle, cycles/neuron, utilization, ecc.), sempre con etichetta THEORETICAL/SIMULATED/SYNTHESIZED/POST-P&R.decisions.log— decisioni architetturali importanti, formatoDEC-XXXX(vedidocs/v2-description.md§27).experiments.log— registro principale, unEXP-XXXXper ogni esperimento end-to-end (config → sim/synth/timing → risultato), rimanda areports/experiments/EXP-XXXX/.errors.log— errori/bug/regressioni incontrati durante lo sviluppo V2 stesso (non i bug V1, già chiusi inhardware/v1/docs/validation/bugs.md).
Campi minimi per entry (§26)
timestamp, experiment_id (se applicabile), git_commit, session/agent,
module, configuration, action, reason, command, result, errors, decision,
next_action
Per synthesis/timing aggiungere: LUT, FF, DSP, BRAM, Fmax, critical path, WNS/TNS. Per simulazione: test, vectors, cycles, PASS/FAIL, bit-exact result, stall cycles, memory wait, utilization.