feat: GF-T exp2 primitive + 4-neuron layer + AX7203 classifier synth runbook (Refs #1764)

[gHashTag]

"все три параллельно" — three deliverables in one PR (batched to avoid docs/NOW.md conflict churn during the ongoing GitHub Actions incident that still blocks merging #1801 + #1802).

A² — gft_exp2.t27: a GF-T exp2 primitive (the softmax building block)

2^x for a signed GF-T16 input → positive GF-T16. Softmax in base 2 is 2^logit / Σ 2^logit, so exp2 is the missing primitive.

Method (all integer, hardware-shaped): |x|→Q16.16 (positive shifts only, no signed-shift ambiguity) → sign-aware floor into integer k + fraction f → 2^x = 2^k·2^f; 2^k is an exact GF-T offset, the 2^f mantissa comes from a Q16 quartic with rounded Horner shifts (coeffs 354,123,29,6).

Prototype-first (debugging doctrine): the poly was fitted + local-searched in Python against the exact mantissa — ≤1 ULP over all 2¹⁶ fractions — and the whole pipeline against true round_to_GFT(2^x) — ≤1 ULP over the logit sweep — before transcribing to .t27. Bit-exact to the committed integer oracle 606/606 (iverilog). Spot-checks exact: 2⁰=1, 2¹=2, 2⁻¹=0.5, 2²=4.

B — gft_layer4.t27: 4-neuron BitNet×GF-T layer

Extends gft_layer3 to 4 neurons (M→N=4): 4 shared GF-T16 activations → 4 trits packed 2 bits each. Doubly-grounded oracle (int-vs-float), iverilog 500/500 bit-exact.

C — docs/synth/CLASSIFIER_AX7203.md: owner-gated flash runbook

Copy-paste flow: gft_classifier4 spec → yosys (synth_xilinx -family xc7) → nextpnr-xilinx → openFPGALoader on ALINX AX7203 (XC7A200T). The final JTAG flash is owner-gated (needs the user at the board). On-silicon "done" = replay gft_classifier4_vectors.txt, class index bit-exact 1500/1500 on-air (mirrors the gft_dot2 #185 proof).

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Fresh seals for GftExp2 + GftLayer4 (seal --verify → MATCH). No compiler change.

Refs #1764

⚠️ GitHub Actions infra incident ongoing (jobs stuck queued repo-wide). If gates stall, it is the same infra issue — all three parts are verified locally (iverilog 606/500, seals MATCH).

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[github-actions]

📓 NotebookLM Notebook linked to this PR

• Notebook ID: b83263109fb055dc
• URL: https://notebooklm.google.com/notebook/b83263109fb055dc

This notebook contains session context, decisions, and artifacts for this work.

[github-actions]

PR Dashboard

Generated at: 2026-08-06 22:21:55 UTC

• feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1815 feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 1 total
• feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1813 feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 11 failing / 12 total
• feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1810 feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 11 failing / 12 total
• integration: complete GF-T train+infer stack (all 8 PRs, locally verified) (Refs #1764) #1809 integration: complete GF-T train+infer stack (all 8 PRs, locally verified) (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 10 failing / 17 total
• demo: GF-T learns — end-to-end on-device training proof (Refs #1764) #1808 demo: GF-T learns — end-to-end on-device training proof (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 8 failing / 17 total
• feat: GF-T exp2 primitive + 4-neuron layer + AX7203 classifier synth runbook (Refs #1764) #1803 feat: GF-T exp2 primitive + 4-neuron layer + AX7203 classifier synth runbook (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 12 failing / 17 total
• feat(spec): end-to-end GF-T classifier — MLP to GF-T logits to argmax to class (Refs #1764) #1802 feat(spec): end-to-end GF-T classifier — MLP to GF-T logits to argmax to class (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 10 failing / 22 total

Summary

Status	Count
Total Open PRs	7
PRs with Failing Checks	0
PRs with All Checks Green	7
READY	1
FAILING	0
PENDING	0

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=4c1aaad5309a != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).

[github-actions]

PR Dashboard

Generated at: 2026-08-06 22:22:01 UTC

• feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1815 feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 1 total
• feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1813 feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 11 failing / 12 total
• feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1810 feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 11 failing / 12 total
• integration: complete GF-T train+infer stack (all 8 PRs, locally verified) (Refs #1764) #1809 integration: complete GF-T train+infer stack (all 8 PRs, locally verified) (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 10 failing / 17 total
• demo: GF-T learns — end-to-end on-device training proof (Refs #1764) #1808 demo: GF-T learns — end-to-end on-device training proof (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 8 failing / 17 total
• feat: GF-T exp2 primitive + 4-neuron layer + AX7203 classifier synth runbook (Refs #1764) #1803 feat: GF-T exp2 primitive + 4-neuron layer + AX7203 classifier synth runbook (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 11 failing / 17 total
• feat(spec): end-to-end GF-T classifier — MLP to GF-T logits to argmax to class (Refs #1764) #1802 feat(spec): end-to-end GF-T classifier — MLP to GF-T logits to argmax to class (Refs #1764) | Created: 2026-08-06 | Updated: 2026-08-06 | 10 failing / 22 total

Summary

Status	Count
Total Open PRs	7
PRs with Failing Checks	0
PRs with All Checks Green	7
READY	1
FAILING	0
PENDING	0

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=4c1aaad5309a != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).

[github-actions]

📓 NotebookLM Notebook linked to this PR

• Notebook ID: b83263109fb055dc
• URL: https://notebooklm.google.com/notebook/b83263109fb055dc

This notebook contains session context, decisions, and artifacts for this work.

[gHashTag]

Superseded: this branch's content (gft_layer4.t27 + docs/synth/CLASSIFIER_AX7203.md) already landed in master via the integration merge #1809, together with the full GF-T train+infer stack. Closing as redundant.