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vram/MemArbiter: remove unnecessary wires and fields 

While iterating many redundant bits were added. This removes them again,
keeping just (I think) the minimum necessary for the arbitrators to work.
This commit is contained in:
David Anderson 2024-09-08 15:06:27 -07:00
parent 519eddc552
commit e5aabcbf4a
1 changed files with 9 additions and 14 deletions
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23
vram/MemArbiter.bsv
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@ -25,6 +25,7 @@ function Bool mem_ops_conflict(Maybe#(MemArbiterOp#(addr)) a, Maybe#(MemArbiterO
endfunction
// A MemArbiterServer receives requests and emits grants.
(* always_ready *)
interface MemArbiterServer#(type addr);
method Action request(MemArbiterOp#(addr) req);
method Bool grant();
@ -71,6 +72,7 @@ interface MemArbiter#(numeric type num_clients, type addr);
// MemArbiter intances are Connectable: mkConnection(a, b) gives
// conflict priority to a. That is, b only grants requests that
// don't conflict with a's grant.
(* always_ready *)
method Action conflict(MemArbiterOp#(addr) conflict);
method MemArbiterOp#(addr) granted_op();
endinterface
@ -130,13 +132,13 @@ module mkPriorityMemArbiter(MemArbiter#(num_clients, addr))
endmodule
typedef struct {
Bool granted;
Vector#(n, Bool) grant_vec;
UInt#(TLog#(n)) selected;
Maybe#(MemArbiterOp#(addr)) granted_op;
} GrantResult#(numeric type n, type addr) deriving (Bits, Eq, FShow);
// select_grant computes which one entry of requests should be granted.
// select_grant computes which one entry of requests should be
// granted. Priority order is descending starting from
// requests[hipri].
function GrantResult#(n, addr) select_grant(Vector#(n, Maybe#(MemArbiterOp#(addr))) requests,
UInt#(TLog#(n)) hipri,
Maybe#(MemArbiterOp#(addr)) conflict)
@ -152,11 +154,9 @@ function GrantResult#(n, addr) select_grant(Vector#(n, Maybe#(MemArbiterOp#(addr
Tuple2#(UInt#(TLog#(n)),
Maybe#(MemArbiterOp#(addr))) next);
match {.idx, .mreq} = next;
if (mreq matches tagged Valid .req &&& !acc.granted &&& !mem_ops_conflict(conflict, mreq))
if (mreq matches tagged Valid .req &&& acc.granted_op matches tagged Invalid &&& !mem_ops_conflict(conflict, mreq))
return GrantResult{
granted: True,
grant_vec: onehot(idx),
selected: idx,
granted_op: tagged Valid req
};
else
@ -167,9 +167,7 @@ function GrantResult#(n, addr) select_grant(Vector#(n, Maybe#(MemArbiterOp#(addr
let in = zip(map(fromInteger, genVector()), requests);
let rot = rotateBy(in, fromInteger(valueOf(n)-1)-hipri+1);
let seed = GrantResult{
granted: False,
grant_vec: replicate(False),
selected: 0,
granted_op: tagged Invalid
};
return foldl(do_fold, seed, rot);
@ -201,13 +199,10 @@ module mkRoundRobinMemArbiter(MemArbiter#(num_clients, addr))
let res = select_grant(in, high_prio, conflict_in.wget());
grants <= res.grant_vec;
if (res.granted)
if (res.selected == fromInteger(valueOf(num_clients)-1))
high_prio <= 0;
else
high_prio <= res.selected+1;
if (res.granted_op matches tagged Valid .op)
if (res.granted_op matches tagged Valid .op) begin
granted_op_out.wset(op);
high_prio <= validValue(findElem(True, rotateR(res.grant_vec)));
end
endrule
Vector#(num_clients, MemArbiterServer#(addr)) _ifcs = newVector();