Fixed grant bug

Just becasue we have a grant id doesn't mean that anything has actually
been granted...

bs/Bus/Bus.bs

@@ -14,16 +14,14 @@ import FIFOF
 import SpecialFIFOs
 import Printf
 
-busRequestToAddr :: BusRequest -> Addr
-busRequestToAddr req = case req of
-    BusReadRequest (ReadRequest addr _) -> addr
-    BusWriteRequest (WriteRequest addr _) -> addr
-
--- Create a Bus Module that supports multiple clients and servers
+-- Creates a Bus Module that supports multiple clients and servers
 -- submitting requests and simultaneously returning responses.
--- Responses can be consumed by clients out of order as all client
--- submitted requests are tagged - and servers keep that tag
--- when responding.
+-- Responses can be consumed by clients out of order(useful when some
+-- servers respond before others) as all client submitted requests are
+-- tagged with tags that are unique for the duration of the transaction
+--  - and well-behaved servers should keep that tag when responding.
+
+-- Explicitly inform the compiler that log2 n <= log2(n + 1)
 mkBus :: (Add n (TLog numServers) (TLog (TAdd numServers 1)))
       => (Addr -> Maybe (MkServerIdx numServers))
       -> Module (Bus inFlightTransactions numClients numServers)
@@ -32,13 +30,15 @@ mkBus serverMap = do
     tagEngineByClientVec :: Vector numClients (TagEngine inFlightTransactions)
     tagEngineByClientVec <- replicateM mkTagEngine
 
-    -- There are `numClients` clients, each of which needs its own arbiter as
-    -- there are up to `numServer` servers that may wish to submit a response
-    -- to a given client. Furthermore the rule that routes client requests to
-    -- servers makes for another potential requestor as it may determine that
-    -- a request is unmappable and instead opt to form and submit a
-    -- `BusError UnMapped` response directly to a client response arbiter. Thus
-    -- we must arbit between a total of `numServers + 1` requestors.
+    -- There are `numClients` clients, each of which needs its own client 
+    -- response arbiter as there are `numServer` servers that may wish to 
+    -- submit a response to a given client. Furthermore the rule that routes
+    -- client requests to servers makes for another potential submitter to
+    -- the client response arbiter as it may determine that a request is
+    -- unmappable and simply bypass submitting the request to a server,
+    -- instead opting to form a `BusError UnMapped` response to be submitted
+    -- directly to a client response arbiter. Thus the client response arbiter
+    -- must arbit between a total of `numServers + 1` requestors.
     responseArbiterByClient :: Vector numClients (Arbiter.Arbiter_IFC (TAdd numServers 1))
     responseArbiterByClient <- replicateM (mkArbiter False)
 
@@ -48,9 +48,6 @@ mkBus serverMap = do
     requestArbiterByServer :: Vector numServers (Arbiter.Arbiter_IFC numClients)
     requestArbiterByServer <- replicateM (mkArbiter False)
 
-    dummyVar :: Reg(Bool)
-    dummyVar <- mkReg False
-
     -- Queues to hold requests from clients
     clientRequestQueues :: Vector numClients (FIFOF (TaggedBusRequest inFlightTransactions))
     clientRequestQueues <- replicateM (mkSizedBypassFIFOF (valueOf inFlightTransactions))
@@ -59,8 +56,11 @@ mkBus serverMap = do
     clientResponseQueues :: Vector numClients (FIFOF (TaggedBusResponse inFlightTransactions))
     clientResponseQueues <- replicateM (mkSizedBypassFIFOF (valueOf inFlightTransactions))
 
-    -- The following two vectors of FIFOs make it easier to push/pull data to/from internal
-    -- server methods:
+    -- The following two vectors of single depth FIFOs make it easier to push/pull data 
+    -- to/from internal server methods as they provide back-pressure in both directions,
+    -- and behave as a wire when queue is empty.
+    -- If looking at the example bus.drawio diagram, the following two vectors effectively
+    -- correspond to the two arrows going from the blue box to the servers.
     consumeRequestQueues :: Vector numServers (
                                         FIFOF (
                                             MkClientTagType numClients,