Module hash_table 

Transactional cuckoo table, nine true synchronous RAM banks of 64 entries. Transactions are serialized; responses hold until consumed. Reset discards all in-flight work and scrubs every RAM address before accepting another request.

The central invariant is that no request can observe an unfinished eviction. A successful insertion keeps its writes; an exhausted insertion restores every overwritten entry before publishing failure. Holding the response also holds off the next request, which makes the transaction boundary clear.

State encoding: 0 scrub, 1 idle/admit, 2 launch RAM addresses, 3 inspect RAM results, 4 undo one journal entry. New requests launch their RAM addresses on admission. Evicted victims still use state 2 to launch their new address. Reset clears the table; it does not restore a persistent pre-reset snapshot.

Transfers occur on rising edges with valid and ready asserted. Producers retain valid and payload until transfer. Simultaneous lookup/update requests alternate admission preference; a stalled response blocks further admission. Reset suppresses request and response handshakes.

Structs

Entry

One physical RAM entry; key and value are meaningful only while valid.

HashTable

Nine 64-entry synchronous RAM banks with key64/value16 and bounded insertion. Reset scrubs all contents. Failed insertion rolls back before reporting failure.

HashTableIn

Requests and response-consumer readiness for the serialized table.

HashTableOut

Admission readiness, held responses, and reset/diagnostic status.

LookupReq

One lookup; hold its fields until valid && lookup_request_ready.

LookupResp

A held result. A miss always returns value zero; consult hit to distinguish that miss from a stored zero value.

Registers

Transaction controller state, including the twelve-entry undo journal.

Undo

The old contents of one physical location, recorded before overwriting it. Repeated locations remain separate records because rollback is ordered.

UpdateReq

op=0 upsert, op=1 delete. This is a semantic API, not HLS enum packing.

UpdateResp

Upsert success means the entry is installed. Delete success means an entry existed. Failed upsert means all eviction writes have already been undone.

Functions

hash_table_kernel

Advance admission, synchronous RAM access, or one rollback step. Decisions read the registered snapshot; writes describe the next edge.