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FPGA-Neural/hardware/v2/logs/simulation.log
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micheleandClaude Sonnet 5 175f697ae1 feat(v2): M4 Memory Manager + Prefetch Engine, real V1 PSRAM backend
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
2026-09-05 14:39:29 +02:00

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# V2 simulation log -- solo append, mai troncato/sovrascritto (vedi README.md)
# Nessuna entry ancora -- popolato incrementalmente man mano che avanza lo sviluppo V2.
[2026-09-05] EXP-0001/EXP-0002 -- hardware/v2/sim/tb_neural_processor.v
test: 7 cases (16/32/8/8/8/8/64-input jobs; ACT_NONE + ACT_RELU;
extreme INT8 saturation; back-to-back zero-idle-gap tiles)
vectors: regular positive, mixed-sign cancellation, extreme INT8
(-128,-127,-1,0,1,126,127,127 in one 8-lane tile), back-to-back
jobs, 8-tile (64-input) job
simulator: Verilator 5.050 (--binary --timing) -- see decisions.log
DEC-0004 for why Icarus v13.0 is not trusted for this testbench
cycles: not separately profiled at this milestone (throughput/stall
cycle counting deferred to M9 per §22)
PASS/FAIL: 7/7 PASS (ACC_WIDTH=32); 7/7 PASS (ACC_WIDTH=24, EXP-0002)
bit-exact result: V1.y === V2.result_data for every case, both widths
stall cycles / memory wait / utilization: N/A (no Memory Manager yet,
M1 operands fed directly by testbench per the roadmap)
[2026-09-05] EXP-0003 -- hardware/v2/sim/tb_neural_processor_array.v
(N_PROCESSORS=4)
test: 7 cases (single-processor sanity; 4-way same-cycle concurrent
launch with different tile counts; staggered-start 2-processor test)
simulator: Verilator 5.050 (--binary --timing)
PASS/FAIL: 7/7 PASS
bit-exact result: N/A at this milestone (hand-computed expected
values, arithmetic itself already bit-exact-certified vs V1 at M1)
concurrency: confirmed genuine -- in the staggered test, the
later-launched, shorter job (processor 1) completes BEFORE the
earlier-launched, longer job (processor 0), proving independent
progress rather than serialization.
[2026-09-05] EXP-0004 -- hardware/v2/sim/tb_buffers.v
test: 10 cases across activation_buffer/weight_buffer/result_buffer
vectors: extreme INT8 (-128, 127, -100, 100), regular values, full
64-bit tile round-trip (weight_buffer), re-reads confirming earlier
writes undisturbed
simulator: Verilator 5.050 (--binary --timing)
PASS/FAIL: 10/10 PASS
[2026-09-05] EXP-0005 -- hardware/v2/sim/tb_memory_manager.v
test: 3 end-to-end jobs (3-tile/saturating, 1-tile/non-saturating,
5-tile/steady-state-swap), real V1 PSRAM backend chain (unmodified),
real M1 neural_processor
simulator: Verilator 5.050 (--binary --timing)
PASS/FAIL: 3/3 PASS
bit-exact result: PSRAM-read-back result byte matches hand-computed
expectation in every case (independent oracle, not derived from the
RTL under test)
cycles: 446 (3 tiles), 166 (1 tile), 728 (5 tiles) -- real PSRAM
latency dominates, not memory_manager's own control overhead