Module layout 

Where ubft_new keeps its mailboxes in HBM, and what crosses the wire.

A replica never sends a message in the usual sense. It RDMA-writes a few bytes into the same address of every peer’s HBM (each card has the same layout), and every replica reads its own HBM to see what peers wrote. So the layout is the protocol. rhdl_ubft keeps ubft_new’s layout word for word, which lets it run on ubft_new’s RoCE stack and host unchanged.

All addresses are 32-bit word indices into network_ptr (bytes = 4 × word). The mailboxes start after ubft_new’s heartbeat, log and deposit areas, at UBFT_BASE_PTR.

This table is ubft_new’s layout (Mailbox::new). rhdl_ubft keeps the regions, their order and the base, and widens three of them so that a vote binds the value it is for (Mailbox::v2): a prepare is four words (k, m, view, 0), and each vote and flag is two words (tag(view, k), m). The host reads none of the widened regions.

Mailbox	Words	Index	What a peer writes there
prepare	G_T · 2	slot·2 + {0: k, 1: m}	the leader’s proposal: sequence k, value m
will_cert	G_T · N	slot·N + node	fast path, first vote
will_commit	G_T · N	slot·N + node	fast path, second vote
commit	G_T · N	slot·N + node	slow path commit vote
certify_valid	G_T · N	slot·N + node	“my certify share is in place”
certify	G_T · N · 16 · SB	(slot·N + node)·16·SB + word	slow path: the node’s share (SB beats: Ed25519 1, DSig 26)
vc	N · 4	node·4 + {view, slot, k, m}	view change: what the node last saw
vc_valid	N	node	view change record present
newview	4	{view, slot, k, m}	the new leader’s decision
newview_valid	1		new view present
view	32		reserved

Structs

Mailbox

The mailbox bases for a cluster of n replicas and a window of g slots, computed exactly as ubft_new’s ubft() does at init.

Constants

UBFT_BASE_PTR

ubft_new’s UBFT_BASE_PTR (globals.hpp): after NUM_NODES heartbeat words, one sync group’s replication log (2 + 11·5 proposals, 250,000 slots, 2·11·5 queue words) and NUM_NODES deposit words.

UPSTREAM_G_T

ubft_new’s G_T: slots in its window.

UPSTREAM_NUM_NODES

ubft_new’s NUM_NODES: the largest cluster its constants are sized for.