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prism_control_reassembler

Latency1 cycle admission, 2 cycles to first payload byteMemorydual port block RAM

prism_control_reassembler collects bounded, potentially out-of-order CONTROL fragments that share a session cookie and transaction identifier. It emits one ordered payload only after the message is complete.

Contracts

  • Fragment start: accepts a prism_control_header_t and the payload length for one fragment.
  • Fragment byte stream: accepts exactly the bytes belonging to the admitted fragment.
  • Reassembled message: publishes the canonical header, total payload length, and ordered byte stream.
  • Error result: reports a prism_status_e value through an independent ready/valid channel.

Contract behavior

  • Bounds concurrent messages, fragment size, total capacity, and fragment count through elaboration parameters.
  • Registers each fragment request before context matching, isolating packet validation from reassembly state updates.
  • Matches fragments by session cookie and transaction identifier while checking invariant header fields.
  • Accepts duplicate fragments only when their stored content is consistent.
  • Releases a message in fragment-index order after all expected fragments arrive.
  • Reports malformed, conflicting, oversized, or timed-out transactions without publishing a partial request.