T81 Foundation

Drift Decomposition

Last Updated: 2026-03-06 Owner: @t81dev

Explicit mapping of: Spec claim → Implementation reality → Closure plan

No narrative. Each row is a falsifiable statement.


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Drift Matrix

Surface Spec Reference Spec Claim Implementation Reality Gap Closure Plan Owner Target State
TISC ISA spec/tisc-spec.md (Frozen) Opcode semantics are bit-exact and immutable under v1.x Implemented; freeze integrity check runs in CI None Maintain @t81dev Closed
Data Types spec/t81-data-types.md (Frozen) Canonical encoding is bit-stable; soft-float uses strict rounding Implemented; 2026-02-27 audit fixed Cell overflow UB, T81Float signed-zero, T81Map/T81Set enforcement None Maintain; monitor for UB regressions @t81dev Closed
T81VM (non-JIT path) spec/t81vm-spec.md (Beta) Reference interpreter is deterministic for all TISC opcodes Beta — all DCP-scoped opcodes covered by tests; FW-02 closure landed with Axion opcode pre-dispatch isolation from the main VM switch None in this cycle Maintain; monitor regression signals in Axion/VM conformance suites @t81dev Closed
T81Lang — Compiler Bytecode spec/t81lang-spec.md §5 (Draft) Compilation from source to TISC bytecode is bit-exact Fixture-bounded: 16 corpus programs produce deterministic output; full spec-section traceability gap was partially closed 2026-02-25 Bytecode emission is partially traceable — full deterministic compilation-profile language not yet complete Extend fixture corpus and spec-section traceability linkage @t81dev 2026-05-15 Open
T81Lang — Type Frontend spec/t81lang-spec.md §§2-4 (Draft) All language-level types are exposed in lexer/parser/semantic analyzer with deterministic lowering Beta — collection determinism and enforcement hardening landed (BG-06 closure) with determinism coverage in place None in this cycle Maintain; monitor regression signals in determinism suites @t81dev Closed
T81Lang — Serialization spec/t81lang-spec.md (Draft) serialize_canonical is called from the language runtime for all types Collection and T81Graph serialization wiring landed (BG-09 closure) and deterministic signatures verified None in this cycle Maintain; monitor serialization determinism regressions @t81dev Closed
T81Lang — BigInt Precision spec/t81lang-spec.md (Draft) T81BigInt supports arbitrary-precision integers Oversized literals lower to BigIntHandle, serialize deterministically via bigint_pool, materialize in VM as canonical BigInt/1 fraction, and do not silently truncate; JIT deopts BigIntHandle to interpreter path None in this cycle Maintain fail-closed narrowing behavior (Frac2I) and regression coverage @t81dev Closed
T81Graph Surface inventory (non-normative) T81Graph is lowered to VM native opcodes with deterministic serialization VM lowering plus lang-side serialization wiring are complete; determinism coverage in place None in this cycle Maintain as governed non-DCP surface @t81dev Closed
Axion — Privileged Instruction Arbitration spec/axion-kernel.md §1.6 (Draft) AXREAD/AXSET/AXVERIFY arbitration is governed through the policy engine Implemented (bounded): policy engine and opcode-level arbitration hooks present None in this cycle Maintain @t81dev Monitoring
Axion — Policy Enforcement spec/axion-kernel.md §1.9 (Draft) Policy parser, bytecode serialization, and verdict path are deterministic Implemented (bounded): parser, serialization, and guard/trace paths present None in this cycle Maintain @t81dev Monitoring
Axion — Determinism Stewardship spec/axion-kernel.md §1.1 (Draft) Canonical trace is steward across all Axion-visible memory transitions Evidence mapping closure landed (AX-M5) None in this cycle Maintain; re-verify at Beta review cadence @t81dev Closed
Axion — CanonFS Observability spec/axion-kernel.md §1.10 (Draft) CanonFS persistence lifecycle is fully auditable via Axion trace Lifecycle observability evidence closure landed (AX-M6) None in this cycle Maintain; re-verify at Beta review cadence @t81dev Closed
Axion — Complexity Measurement spec/axion-kernel.md §1.3 (Draft) Call-graph complexity and branch-path divergence are measurable Complexity evidence closure landed (AX-M7) None in this cycle Maintain; re-verify at Beta review cadence @t81dev Closed
Axion — Tier Transition spec/axion-kernel.md §2.5 (Draft) Full cognitive-tier promotion/demotion orchestration is governed by Axion Deferred: tier-transition orchestration beyond policy ceilings is out of this cycle Full transition orchestration is unimplemented Governed alongside experimental cognitive-tier maturation post-2026-04-30 @t81dev 2026-06-15 Deferred
T3K Quantization spec/t3k-quantization-spec.md T3K GGUF quantization is bit-exact Repro gate evidence plus governed spec artifact now present (spec/t3k-quantization-spec.md) None in this cycle Maintain @t81dev Closed
Complex Binary Serialization spec/t81-data-types.md (Frozen) T81Complex supports binary pool serialization Binary pool serialization implemented and validated (BG-08 closure) None in this cycle Maintain @t81dev Closed

Summary Counts (2026-03-06)

State Count
Closed 12
Open 1
Deferred 1
Monitoring 2

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