Module fabric 

Historical nine-context, three-lane SHA transport fabric.

This module is deliberately limited to transport. It arbitrates complete [CompressionInput] requests onto three fixed-throughput SHA lanes and routes their fixed-latency [CompressionOutput] responses back to context slots. It does not decide which WOTS task is dependency-ready, store intermediate hashes, or prove signature throughput.

The issue side scans nine context slots from a four-bit round-robin cursor, accepts at most three distinct canonical requests, and advances past the last accepted slot. A valid request is canonical only when its task tag is well formed and the tag’s context field names the slot carrying it. Since a slot is visited once per scan, one context can never occupy two lanes in a cycle.

The return side validates each tag before indexing a context. Malformed and out-of-range tags are rejected. If two lanes nevertheless return to the same context in one cycle, every member of that collision is rejected and the context receives no response. Equal-latency lanes combined with the distinct-issue invariant make that condition unreachable in a correctly integrated design, but detecting it turns an integration fault into an explicit signal rather than silent data loss.

Only the round-robin cursor is registered and reset. Request payloads, response payloads, tags, and router state are purely combinational here.

Architecture status

This central 9-by-3 fabric is a preserved foundation from an earlier architecture study. The selected production signer does not instantiate ShaTransportFabric. Instead, each crate::cluster::LaneLocalCluster keeps four contexts, one lane, response routing, and result framing local; crate::top::Sha256SignerTop replicates that cluster three times. The local topology prevents wide context memory ports from crossing the global boundary and provides twelve total contexts.

Tests of this module establish its own issue/routing behavior only. They do not establish production-signer topology, WOTS dependency scheduling, sustained signature throughput, synthesis, timing, resources, or hardware behavior.

Structs

IssueControlInput

Compact valid/tag view consumed by the emitted-RTL arbitration gate.

IssueControlOutput

Compact arbitration decision used to drive the payload mux.

IssueInput

Nine context-owned requests presented to the round-robin issue kernel.

IssueOutput

Issue grants and the three lane inputs for one cycle.

ResponseControlInput

Compact valid/tag view consumed by the emitted-RTL response gate.

ResponseControlOutput

Compact validated response-routing decision.

ResponseRouterInput

Three compression-lane responses presented to the return router.

ResponseRouterOutput

Per-context routed responses and fail-closed lane status.

ShaTransportFabric

Historical stateful nine-context arbiter plus combinational response router.

TransportInput

Combined request/response ports for ShaTransportFabric.

TransportOutput

Combined issue and return results for ShaTransportFabric.

Constants

CONTEXT_COUNT

Number of context slots in this historical central fabric.

LANE_COUNT

Number of compression-lane slots in this historical central fabric.

Functions

host_issue_oracle

Independent host oracle for one issue-arbitration cycle.

host_response_router_oracle

Independent host oracle for one response-routing cycle.

issue_control_kernel

Fairly select at most three distinct canonical context tags.

issue_requests_kernel

Fairly select at most three distinct canonical context requests.

response_control_kernel

Validate three lane tags and compute their context destinations.

route_responses_kernel

Validate and route three fixed-latency lane responses to nine contexts.

sha_transport_fabric_kernel

Connectivity kernel for ShaTransportFabric.