Promotes EXP-0062's own procedural testbench sequence (prefetch ->
buffer swap -> per-tile gather -> operand streaming -> result
capture) into real synthesizable RTL, wrapping layer_prefetch_ctrl.v
-> layer_weight_buffer.v -> weight_tile_gather.v ->
neural_processor_packed.v behind a 9-state FSM matching
neural_director_packed.v's own per-slot contract.
First run: 4/9 failed, deterministic. Root-caused (not a sequencer
bug): the testbench's own w_base computation wrongly treated it as a
byte address needing *2 conversion; layer_prefetch_ctrl.v expects a
word address directly, and packed_slot.v already passes it through
unconverted to match. Fixed the testbench.
Re-verified: 9/9 PASS, 0 errors, bit-exact results and correct
node_id/result_addr passthrough, entirely self-sequenced (no
testbench-side procedural driving of the sub-modules).
Full writeup in hardware/v2/logs/experiments.log EXP-0065.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
Forked from neural_director.v (M5): dispatches PAIRS of queued jobs
(sharing w_base+n_tiles) to packed-core slots instead of one job per
slot, matching neural_processor_packed.v's A/B job structure. If the
two oldest queue entries don't share w_base/n_tiles, the Director
stalls (never mis-pairs) -- a disclosed scope limitation, not hidden.
Isolated testbench with behavioral per-slot stubs (same DEC-0007 scope
decision as tb_neural_director.v). First run: 3/7 tests failed --
investigated each, root-caused as testbench timing bugs (checking
dispatch state before the Director's own FSM had caught up, and a
held-too-long job_in_valid making push counts ambiguous), not Director
bugs. Fixed the testbench, re-verified: 8/8 PASS, 0 errors.
Full writeup in hardware/v2/logs/experiments.log EXP-0064.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
New hardware/v3/rtl/np_packed_weight_reuse_top.v: flat structural
synthesis wrapper around the EXP-0062-verified module chain (real SDR
SDRAM controller -> layer_prefetch_ctrl.v -> layer_weight_buffer.v ->
weight_tile_gather.v -> neural_processor_packed.v).
Real Vivado post-route: 8/240 DSP48E1 (unchanged, memory path uses
zero DSPs), WNS -2.502ns @ 200MHz -> Fmax ~133.3MHz, only -1.2% vs
the isolated single core (134.9MHz, EXP-0059). Real memory-path
control logic adds negligible Fmax cost at this scale.
Full writeup in hardware/v2/logs/experiments.log EXP-0063.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
Closes the gap EXP-0058 left testbench-only: assembling P_IN
sequential layer_weight_buffer.v byte reads into one weight_data
tile bus, as real RTL instead of a testbench driver task. Avoids the
runtime-indexed-part-select anti-pattern already found and fixed once
in neural_director.v (ERR-0027-class Fmax collapse) by using a fixed
shift-concat instead.
Verified in isolation against a real, unmodified layer_weight_buffer.v:
37/37 tests, 0 errors, bit-exact across sequential, back-to-back, and
non-sequential/repeated (real reuse-position-style) access patterns.
Full writeup in hardware/v2/logs/experiments.log EXP-0061.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
New hardware/v3/rtl/np_packed_array.v: flat array of 8 unmodified
neural_processor_packed.v instances, fully independent I/O, zero
shared arbiter/Director logic -- isolates exactly one variable
(DSP/placement density) from EXP-0059's single-core baseline.
Real Vivado post-route: 64/240 DSP48E1 (26.67%), WNS -2.592ns @
200MHz -> Fmax ~131.7MHz, only -2.4% vs the single-core 134.9MHz.
Placement density alone is NOT the main driver of the ECP5-era gap
between isolated-core and full-system Fmax -- narrows the question
for the still-unbuilt real Director/arbiter/memory integration.
Full writeup in hardware/v2/logs/experiments.log EXP-0060.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
New hardware/v3/ (Artix-7 port, branch v3-artix7): the compute engine
that makes the 100x-vs-ESP32 target theoretically reachable on
XC7A100T's 240 DSP48E1 budget.
mac2_dsp_packed.v: packs 2 INT8 MACs sharing one resident weight into
a single DSP48-shaped 25x18 multiply, exploiting this project's own
weight-stationary reuse pattern (layer_weight_buffer.v, EXP-0057/0058)
where one weight is genuinely multiplied against many different
activations. Verified exhaustively: 16,777,216/16,777,216
(weight,x0,x1) combinations, 0 errors.
Two real bugs found and fixed during that verification (both purely
arithmetic/RTL, not toolchain-related):
1. An off-by-one in a declared wire width caused Verilog's part-select
unsigned-by-default rule to corrupt sign extension on the upper
product field -- ~50% of vectors failed.
2. After fixing (1), still ~50% failed: concatenating two independently
sign-extended fields ({sext(x1,9), sext(x0,16)}) is NOT equivalent
to the real arithmetic sum x1*2^16+x0 whenever the lower field is
negative (its own two's-complement encoding "bleeds" an extra 2^16
into the concatenated value). Fixed by building the packed operand
with an explicit arithmetic shift-and-add instead of concatenation.
neural_processor_packed.v: full port of hardware/v2/rtl/
neural_processor.v's pipeline (same stage count/structure), doubled on
the accumulator/bias/activation/saturation side to process two
weight-reuse positions per weight-tile stream. Verified against TWO
real hardware/v2/rtl/neural_processor.v instances (job A / job B, same
shared weight, independent activations) -- 18/18 PASS, 0 errors,
covering the functional sweep, INT8 extremes, and back-to-back jobs.
A third real bug found in the process (in the new testbench, not the
RTL): clearing operand_valid/tile_last in the same simulation delta as
the handshake edge that should register tile_last=1 races against the
DUTs' own FSM evaluation of that same edge -- the same pulse-clearing
race class found three times already today in hardware/v2/sim (EXP-0058
and its follow-up commits). Fixed the same way: hold the pulse past the
edge with a real time delay (#1) before clearing.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
micheleandClaude Sonnet 5