8b4d4c1b57
refactor(cam): remove read noise from noise architecture (Phase 2)
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- Make cam_read_noise a pass-through module, removing all noise injection logic
- Switch write noise to use noise_mask_bernoulli instead of noise_mask_grouped
- Add state machine to cam_write_noise for mask generation timing
- Remove noise_mask_grouped.sv (no longer needed)
- Remove read noise parameters from cam_noisy and cam_top
- Update simulation and benchmark code to reflect read noise removal
- Sync documentation to reflect Phase 2 architecture
2026-05-26 23:45:52 +08:00
e1bed00cc4
feat(retrieval): add CAM retrieval benchmark with topk scoring and read noise support
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- Add cocotb benchmark infrastructure under hw/sim/benchmarks/retrieval/ with Makefile
- Implement test_retrieval_benchmark.py supporting configurable topk-k, read/write noise
- Add cluster-based synthetic dataset generator with configurable bit-flip rates
- Add reference model functions: match_topk, match_topk_from_scores, score_rows_with_read_noise
- Add .justfile shortcuts: cam-test-retrieval-no-noise, cam-test-retrieval-read-noise
- Add TOPK_K to Verilator EXTRA_ARGS via cocotb-common.mk
- Add unit tests for topk sorting logic and stateful read-noise scoring
2026-05-22 19:04:54 +08:00
8f59a287c4
feat(hw): add banked CAM pipeline with grouped read/write noise
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- Add cam_core_banked.sv with 8-lane banked CAM core
- Add cam_write_noise.sv and cam_read_noise.sv for grouped noise injection
- Add noise_mask_grouped.sv generating grouped flip masks from 128-bit PRNG
- Add match_engine_pipeline.sv with multi-stage pipelined top-1 selection
- Add popcount_pipeline.sv for pipelined popcount operations
- Refactor test_cam_basic.py with parametrized DUT introspection helpers
- Add Python ref_model match_top1_with_read_noise() for read noise verification
- Update Makefile with separate WRITE_NOISE_* and READ_NOISE_* parameter groups
- Add new testbenches: test_cam_core_banked, test_cam_read_noise,
test_cam_write_noise, test_match_engine_pipeline, test_ref_model_noise
breaking change hint: NUM_ROWS default changed from 512→4096, LANES from 16→8
2026-05-13 18:22:28 +08:00
cbafc4524e
feat(cam): migrate noise generation from xorshift64 to xorshift128
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- Replace NOISE_GEN_BITS/NOISE_SAMPLE_BITS parameters with unified NOISE_BITS
- Use xorshift128 (random128) instead of xorshift64 for PRNG
- Add flip_mask_next combinational helper for single-cycle mask computation
- Add random_enable signal to advance PRNG only on accepted noisy writes
- Simplify FSM by removing mask_group_idx counter
- Update parameter validation: GROUP_BITS (= HASH_BITS/NOISE_BITS) must equal 64
- Update ref_model.py and tests to match new seed convention: {seed, seed}
- Update Makefile and sweep_noise.py with renamed parameters
2026-05-05 20:19:22 +08:00
2da17e101b
feat(rtl): migrate CAM interface to handshake protocol with integrated noise generation
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BREAKING CHANGE: CAM write and query interface replaced with standard valid/ready
handshake. wr_en/wr_row/wr_hash → wr_valid/wr_ready/wr_addr/write_hash.
External noise_mask_lanes_flat removed; noise generation now handled internally
by cam_noisy module with configurable rate via parameters.
- cam_top: add parameters (NOISE_EN, NOISE_RATE_NUM/DEN, NOISE_GEN/SAMPLE_BITS, NOISE_SEED)
- cam_top: replace cam_core with cam_noisy (integrated noise generation)
- match_engine: remove external noise_mask_lanes_flat input
- hw/sim: update Makefile with noise parameters and compile args
- hw/sim/model: add generate_write_flip_mask() and xorshift64() matching RTL behavior
- hw/sim/tests: adapt testbench to new handshake protocol
2026-05-04 18:03:06 +08:00
f71bf06484
feat(hw): add XNOR-popcount CAM design with cocotb verification
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Implement a multi-lane Content Addressable Memory (CAM) that scores
rows by XNOR popcount against a query hash and returns the top-1 match.
RTL modules:
- popcount: parallel group-based population count
- argmax_update: iterative best-match tracking with tie-break
- cam_core: parameterized scanning engine (NUM_ROWS/HASH_BITS/LANES)
with optional SIM_NOISE and SIM_DEBUG ifdef guards
- cam_top: thin wrapper exposing cam_core ports
Verification:
- Python reference model (ref_model.py) for score-level golden comparison
- cocotb testbench (test_cam_basic.py) covering write/query/reset and
external noise mask scenarios with score debug verification
- Noise sweep script (sweep_noise.py) measuring top-1 stability under
configurable bit-flip rates
- Verilator-oriented Makefile with parameterizable compile options
2026-05-02 23:26:16 +08:00
