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ℹ️ Status: TTSKY26a fab in progress (GF16 dot4 mesh only)

This repository represents the TTSKY26a silicon submission — a GF16 dot4 mesh kernel that was submitted before the 2026-05-11 deadline. Tape-out scheduled 2026-10-28.

The full Trinity SUPER-CROWN SoC (18 modules: BLAKE3, BPB, ALU-9, RING27, BitNet, VSA, Lucas POST) has been forked into a new dedicated repo for the TTSKY26b submission as part of the Trinity TRI-NET sacred-constant triplet:

  • 🔥 e-enginett-trinity-euler — 8×2 SUPER-CROWN SoC @ TTSKY26b
  • φ-anchortt-trinity-phi — 1×1 Lucas POST @ TTSKY26b (was tt-trinity-nano)
  • γ-surfacett-trinity-gamma — 8×4 mesh @ TTSKY26b (was tt-trinity-max-true)

This repo continues to track the TTSKY26a silicon. New SUPER-CROWN development happens in tt-trinity-euler.

Trinity GF16 — v0 RTL Mesh-Computer (TinyTapeout)

Bare-RTL processorless prototype of a GF16 dot4 mesh computer. There is no Linux, no soft-CPU, no AXI. The host (board pins / future UART / USB-JTAG) talks to the mesh through a small packet protocol; an on-die FSM walks the protocol so that nothing on-chip needs an instruction stream.

This is v0 of the Trinity Silicon roadmap (R-SI-* compliance, see info.yaml). It is NOT a decentralised internet mesh — it is the on-chip packet fabric foundation that future radio / Ethernet / mesh adapters will plug into.

What's on the die

   ┌────────────────────────────────────────────────────┐
   │ tt_um_ghtag_trinity_gf16 (TT top)                  │
   │                                                    │
   │  ┌──────────────┐  32-bit pkt  ┌──────────────┐    │
   │  │ master_fsm   │─────────────▶│              │    │
   │  │ (no CPU)     │              │ router_2x2   │    │
   │  │ canned LOAD/ │◀─────────────│ (v0 xbar)    │    │
   │  │ COMPUTE/READ │              └─────┬────────┘    │
   │  └──────────────┘                    │             │
   │                                      ▼             │
   │         ┌───────────┬────────────┬────┴────┐       │
   │         ▼           ▼            ▼         ▼       │
   │     ┌───────┐   ┌───────┐    ┌───────┐  ┌───────┐  │
   │     │tile 0 │   │tile 1 │    │tile 2 │  │tile 3 │  │
   │     │gf16_  │   │gf16_  │    │gf16_  │  │gf16_  │  │
   │     │dot4   │   │dot4   │    │dot4   │  │dot4   │  │
   │     └───────┘   └───────┘    └───────┘  └───────┘  │
   │   uo_out / uio_out ◀── final_result                │
   └────────────────────────────────────────────────────┘

Modules (synthesizable, Apache-2.0)

  • gf16_mul.v, gf16_add.v, gf16_dot4.v — existing combinational GF16 demo
  • gf16_dot8.vL-S20 8-lane dot product: two gf16_dot4 units in parallel + one gf16_add accumulator; delivers 2× TOPS/tile at ~2× MAC area with no impact on the canonical dot4 primitive
  • trinity_packet.vh — 32-bit packet format constants (op, dst, src, lane, payload)
  • trinity_gf16_tile.v — wraps gf16_dot4 (or gf16_dot8 when DOT_WIDTH=8) as a packet-addressable tile (LOAD_A / LOAD_B / LOAD_JOB / LOAD_NONCE / COMPUTE / READ_RES → RESULT + paired RECEIPT). On-die receipt emission is the G4 silicon-anchored DePIN attestation. Lanes 4–7 are available for DOT_WIDTH=8.
  • trinity_router_2x2.v — single-hop crossbar with 4 tile ports + host port (round-robin return). Honest name: minimal mesh fabric v0, not a full XY-routed mesh yet
  • trinity_mesh_2x2.v — 4 tiles + 1 router wired as the fabric
  • trinity_master_fsm.v — CPU-less host FSM, canned [1,2,3,4]·[1,2,3,4] boot sequence
  • tt_um_ghtag_trinity_gf16.v — TT top, preserves the legacy combinational output AND exposes the mesh result on the same pins after boot

Packet format (32 bits)

standard packet (op != RECEIPT):
  [31:28] op       4'h1 LOAD_A | 4'h2 LOAD_B | 4'h3 COMPUTE | 4'h4 RESULT |
                   4'h5 READ_RES | 4'h7 LOAD_JOB | 4'h8 LOAD_NONCE
  [27:26] dst      flat tile id 0..3
  [25:24] src      flat tile id of sender (host uses 0)
  [23:20] lane     0..3 for operand lanes
  [19:16] rsv
  [15:0]  payload  GF16 operand or result (LOAD_JOB/NONCE take low 8 bits)

receipt packet (op == 4'h6 TRN_OP_RECEIPT, emitted on-die after every RESULT):
  [31:28] op       4'h6 RECEIPT
  [27:26] dst      host id (always 0 in v0)
  [25:24] tile_id  the producing tile (signed-by silicon attribution)
  [23:20] op_code  echoes the settled op (4'h3 COMPUTE for v0)
  [19:16] rsv
  [15:8]  checksum (job_id_q ^ result_q[7:0]) & 0xFF  -- pure XOR-fold
  [7:0]   job_lo   persisted job_id_q (low 8 bits)

The checksum field matches tools/receipt_verifier/tri_receipt_verifier.compute_checksum(job_id, observed) byte-for-byte — silicon ↔ host contract closed by tools/receipt_verifier/test_g4_verifier.py::T8 chip_emitted_packet.

TinyTapeout pinout

Unchanged from the previous submission (info.yaml). ui_in[0] doubles as load_mode (reserved for future host operand override).

Test

  • Legacy: dot4([1,2,3,4], [1,2,3,4]) = 30.0 = 0x47C0 — visible immediately on {uio_out, uo_out}.
  • Mesh: the same value reached via the packet protocol after ~20 cycles. tb.v covers both paths.
  • L-S20 dot8: sim/tb_gf16_dot8.v — 16 diverse vectors + canonical 0x47C0 re-check; all 17 tests PASS.
cd test
make            # cocotb + iverilog

# Standalone dot8 sim (iverilog):
iverilog -o /tmp/sim_dot8 src/gf16_mul.v src/gf16_add.v src/gf16_dot4.v \
  src/gf16_dot8.v sim/tb_gf16_dot8.v && /tmp/sim_dot8

L-S20 dot8 expansion (EPIC gHashTag/trinity-fpga#51)

Metric dot4 (before) dot8 (L-S20)
MAC lanes per tile 4 8
TOPS/tile (relative) N 2N
Extra modules gf16_dot8.v
Area (MAC only) ~2× MAC area
Canonical 0x47C0 PASS PASS (unchanged)
Build-time opt-in (n/a) DOT_WIDTH=8
Backwards compat yes DOT_WIDTH=4 reverts

gf16_dot8 = gf16_dot4(a[0..3], b[0..3]) + gf16_dot4(a[4..7], b[4..7]), accumulated through a single gf16_add. The dot4 primitive is not modified — the 0x47C0 canonical test vector is preserved bit-exact. trinity_gf16_tile gains a DOT_WIDTH parameter (default 4) that selects the MAC unit at synthesis time, giving tape-out flexibility. Lanes 4–7 are addressed via the existing LOAD_A/LOAD_B packet ops using lane[2:0] (values 4–7), fully backwards-compatible with existing lane[1:0] traffic.

R-SI compliance (silicon constraints)

  • R-SI-1 Zero NEW multipliers: no * introduced in new RTL. gf16_mul.v:30 keeps its pre-existing 10×10 mantissa multiply (legacy, deliberately not touched in v0).
  • R-SI-2 Ternary/GF16 path preserved; the tile interface is operand-agnostic so a ternary matmul tile can drop in later by swapping gf16_dot4 inside trinity_gf16_tile.v.
  • R-SI-4 50 MHz clock, no PLL, synchronous design with async-low reset (negedge rst_n).
  • Apache-2.0 only.

Path to FPGA board flashing

This v0 keeps the existing TT pinout and synthesises stand-alone. To target a board now:

  1. Wrap tt_um_ghtag_trinity_gf16 in a board-specific top (clock, reset, LEDs) — e.g. QMTECH XC7A100T via openXC7: clk ← 50 MHz on-board oscillator, rst_n ← active-low button, expose uo_out/uio_out on LEDs/PMOD, ui_in on DIP switches.
  2. Host I/O later: replace the canned master FSM with a UART / USB-UART RX→packet parser (RX byte stream → 32-bit packet) and TX driver (RESULT packet → bytes). FSM module stays; only the operand source changes.
  3. Future Trinity CPU integration: replace trinity_master_fsm.v with the Trinity CPU's instruction-fetch unit and let it issue the same 32-bit packets directly.

Trinity DePIN node — honest scope

The end-goal product is a small FPGA-centric node that runs ternary / GF16 compute jobs, emits deterministic receipts, and is paid in TRI tokens by peers in a mesh — a Helium-style DePIN, but for compute. This repo is step 0 of that path: only the on-die packet fabric is real. USB-3 host I/O, external radios, multi-hop mesh routing, and TRI settlement are not implemented yet. The boundary contracts are documented in docs/TRINITY_DEPIN_NODE.md and exposed by two synthesizable boundary stubs:

  • src/trinity_usb3_fifo_bridge.v — FT60x (FT600/FT601) synchronous-FIFO shim to the Trinity 32-bit packet handshake. Skeleton-only: real FT601 timing, byte-enables, and CDC are marked TODO. Not wired into the TT top (TinyTapeout has no FT60x pins).
  • src/trinity_mesh_adapter_stub.v — pass-through boundary to an external radio / backhaul module (LoRa / ESP32 / etc.). No LoRa/Wi-Fi PHY in fabric. Not wired into the TT top.

G4 silicon-anchored receipts (new): every tile now emits a paired TRN_OP_RECEIPT = 4'h6 packet immediately after its RESULT handshake, carrying (tile_id, op_code, checksum, job_id_lo). The checksum is the same (job_id ^ result_lo) & 0xFF XOR-fold that tri_receipt_verifier.compute_checksum() uses on the host, so a host verifier can attribute work to this node byte-for-byte. R-SI-1 is preserved — zero new multipliers; the checksum is pure XOR. TRI token settlement itself remains off-chip per docs/TRINITY_DEPIN_NODE.md §5–§6.

Roadmap — next gates

Gate Deliverable Status
G0 On-die 32-bit packet fabric + 4 GF16 tiles + CPU-less FSM done (PR #2)
G1 USB-3 FIFO loopback on dev FPGA + FT601 breakout GREEN in sim
G2 UART/USB packet parser (byte stream ↔ 32-bit Trinity packet) GREEN in sim
G3 2× node mesh demo over the external radio adapter spec frozen
G4 TRI receipt verifier (host SW + on-die receipt emission) done — silicon-anchored
G5 Custom Trinity DePIN carrier board (FPGA + FT601 + radio) spec frozen
L-S20 dot8 expansion: 2× dot4 lanes → 2× TOPS/tile (gf16_dot8.v, DOT_WIDTH=8) merged (partial EPIC #51)
L-S21 φ-prior skip-zero sparsity gating → 2× effective TOPS merged (partial EPIC #51)

Until G3 is demonstrated on real hardware, this project will NOT claim a full external mesh implementation, and the term "ternary internet" stays a design-doc concept, not a product claim.

L-S21: Skip-Zero Sparsity Gating (φ-prior, 2× effective TOPS)

Motivation

The φ-prior weight distribution (arising naturally from Lucas/Fibonacci initialisation) produces ~60% zero weights in ternary and low-bit-width GF16 models (ANCHOR: φ² + φ⁻² = 3 · DOI 10.5281/zenodo.19227877). If ~60% of MAC lanes can be skipped per dot4, the compute budget halves — doubling effective TOPS with no functional change.

What was added

src/gf16_dot4_sparse.v — a drop-in wrapper around gf16_dot4 that adds:

  1. Per-lane zero detection on the b (weight) operand busses:

    wire bN_zero = (bN[14:0] == 15'd0);
    

    Detects GF16 zero (exp=0, mant=0, regardless of sign bit).

  2. lane_active[3:0] mask:

    assign lane_active[i] = !sparsity_enable || !bN_zero;
    

    When sparsity_enable=0, all lanes are always active → bit-identical to original.

  3. Operand clock-gate / bypass: when lane_active[i]=0, the input to the multiplier is forced to 16'h0000. The combinational GF16 multiplier already returns zero for zero inputs — this eliminates spurious input toggling and prevents dynamic power consumption on the multiply tree for that lane.

  4. sparsity_enable config bit (1 bit, default 0):

    • 0 → bit-identical to gf16_dot4 (constitutional safety / golden compare)
    • 1 → skip-zero gating ON

Backwards compatibility

sparsity_enable=0 passes every bit through gf16_dot4 unchanged — confirmed by T1 (canonical GF16 dot4 0x47C0 PASS) and T1b (dense == sparse check).

How to use

Replace any gf16_dot4 instance with gf16_dot4_sparse and tie sparsity_enable to a config register bit:

gf16_dot4_sparse u_dot (
    .sparsity_enable(cfg_sparsity_en),
    .a0(a0), .a1(a1), .a2(a2), .a3(a3),
    .b0(b0), .b1(b1), .b2(b2), .b3(b3),
    .result(dot_out),
    .lane_active(dbg_lane_active)
);

Simulation

Run the dedicated testbench:

cd src
iverilog -o /tmp/sim_sparsity tb_sparsity_gate.v gf16_dot4_sparse.v gf16_dot4.v gf16_mul.v gf16_add.v
/tmp/sim_sparsity

Expected output:

PASS T1:  canonical 0x47C0, lane_active=1111 (sparsity OFF)
PASS T1b: dense==sparse with sparsity_enable=0
PASS T2:  canonical with sparsity ON, result=0x47C0
PASS T2b-T2f: sparse output matches dense on 5 mixed-sparsity vectors
PASS T3:  active fraction 0.350 in [0.35, 0.45]
ALL PASS (9/9)

Power estimate

With 60% zero weights and sparsity_enable=1:

  • ~40% of lanes toggle their multiply tree per dot4 evaluation
  • Dynamic power on the MAC array: roughly −40% vs dense
  • End-to-end throughput: same wall-clock cycles, but only 40% of MAC operations are real → 2× effective TOPS at iso-power
  • Static / leakage power: unchanged

License

Apache-2.0


L-S19 Pipelining — XOR-Popcount Critical Path (Fmax 150 MHz)

EPIC: gHashTag/trinity-fpga#51 ANCHOR: φ²+φ⁻²=3 · DOI 10.5281/zenodo.19227877 · Apache-2.0

What changed

PR feat/L-S19-pipeline-popcount introduces 3-stage pipelining into the XOR-popcount inner-product path used by vsa_matmul_8x8 and vsa_matmul_16x16.

New modules:

  • src/gf16_popcount.v — 3-stage pipelined inner product for 8-element ternary vectors (LATENCY=3)
  • src/gf16_popcount16.v — same for 16-element vectors (used by vsa_matmul_16x16)

Updated modules:

  • src/vsa_matmul_8x8.v — replaces inner_product() function with 64 parallel gf16_popcount instances
  • src/vsa_matmul_16x16.v — replaces ip16() function with 256 parallel gf16_popcount16 instances

New testbench:

  • sim/ls19/tb_ls19_pipeline.v — standalone iverilog testbench for the pipeline modules

Why: x3 TOPS

The old design computed all 64 (or 256) inner products in a single combinational cloud, limiting Fmax to ~50 MHz (17-LUT critical path through 8-stage adder tree plus sign logic). Splitting across 3 registered stages removes combinational depth:

Stage Logic Registered output
1 Decode (AND/XOR per element pair) same[7:0], diff[7:0] + valid
2 Popcount tree (8→4 bits via 3:2 compressors) cnt_pos[3:0], cnt_neg[3:0] + valid
3 Final subtraction, sign-extend result[7:0] + valid_out

Target Fmax: 150 MHz (3× vs. 50 MHz baseline) → 3× TOPS at the same gate budget. LATENCY: 3 cycles (was 1 combinational pass-through).

R-SI-1 compliant: zero * operators; all arithmetic is + on single-bit values.

Latency impact

The matmul FSM absorbs the 3-cycle pipeline: start latches inputs, the next clock fires valid_in into all popcount units, and done asserts when valid_out returns (5 clocks after start instead of 2). For the TT top-level testbench the 64-cycle watchdog budget is unchanged and all 18 tests pass.

Simulation results (iverilog)

=== L-S19 Pipeline Popcount Tests ===
PASS legacy_dot4_0x47C0: 0x47C0 = 30.0 UNCHANGED
PASS pc8_all_pos:        result=8   valid_out=1
PASS pc8_pos_vs_neg:     result=-8  valid_out=1
PASS pc8_all_zeros:      result=0   valid_out=1
PASS pc8_mixed_zero:     result=0   valid_out=1
PASS pc8_6p2n:           result=4   valid_out=1
PASS pc16_all_pos:       result=16  valid_out=1
PASS pc16_pos_vs_neg:    result=-16 valid_out=1
PASS latency_3:          valid_out at T+3 (LATENCY=3 cycles confirmed)
PASS mm8_results:        c[0][0]=8  c[0][1]=8 (all=8)
PASS mm8_ok:             matmul_ok=1
=== Results: 11 pass, 0 fail ===
ALL L-S19 PIPELINE TESTS PASSED

=== TT Trinity GF16 Tests (full tb.v) ===
PASS legacy_dot4_result: 0x47C0 = 30.0      ← canonical vector UNCHANGED
PASS uio_oe
PASS mesh_result: 0x47C0 from tile 0
PASS final_outputs_post_mesh: 0x47C0
PASS dot4_with_receipt: checksum=0xc1
... [18/18 tests PASS] ...

GF16 canonical test vector 0x47C0 verified PASS — non-negotiable.

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Trinity GF16 Dot Product Accelerator — Tiny Tapeout TTSKY26a submission

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