Spec: unified MEMMOVE accelerator

[nicole-graus]

Description

Specifies the accelerator implemented in #984.

• New MEMMOVE chapter covering memcpy, memmove, memset and commit. The destination domain and the read/write timestamp order are decoded from the entry point, never chosen by the caller: is_set from the syscall number, is_commit from which bus the first row accepted from, both carried inside MEMMOVE_NEXT so a sequence cannot change functionality midway.
• COMMIT is now one row per ecall: it keeps the syscall number and the x254 update, and defers the byte loop over COMMIT_DEFER. CNB is retired.
• Adds the ADDNW template, which is what rules out a sequence closing into a ring.
• Allocates ECALL -30 (copy) and -32 (memset), and lists -31 as reserved for HINT so it is not handed out twice.

[github-actions]

Kimi Code Review

⚠️ Review failed: Kimi API request failed with status 401

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Automated review by Kimi (Moonshot AI)

[github-actions]

Codex Code Review

• Medium — Commitment indexing becomes inconsistent above 4 GiB. In memmove.toml:350, ADDNW normalizes dst_incr into two 32-bit limbs, but COMMIT and the existing commitment-domain convention represent indices as [index, 0]. After crossing 2^32, subsequent rows emit addresses such as [8, 1] instead of [2^32 + 8, 0]. These are different memory tuples, so otherwise valid commitments cannot balance against the verifier’s output. Preserve scalar indexing for commitments, or update the producer and verifier to use normalized indices consistently.

[github-actions]

Kimi Code Review

⚠️ Review failed: Kimi API request failed with status 401

---

Automated review by Kimi (Moonshot AI)

[github-actions]

Codex Code Review

• Medium — Commitment indices change representation after 4 GiB (memmove.toml). dst_incr normalizes the commitment index into two 32-bit limbs, while COMMIT and the verifier use [index, 0]. A write spanning index 2^32 therefore emits [0, 1] where the verifier expects [2^32, 0], making valid output unprovable. Preserve the existing field-valued index arithmetic for commitments, or update the producer and verifier to use the same normalized representation.