step by step - building the rule

bs/Bus.bs

@@ -1,7 +1,55 @@
-package Bus(a) where
+package Bus(mkBus) where
 
 import Types
 import BusTypes
+import TagEngine
+import Vector
+import Util
+import Arbiter
 
-a :: UInt 5
+clientRequest :: Arbiter.ArbiterClient_IFC -> Action
-a = 3
+clientRequest ifc = ifc.request
+
+busRequestToAddr :: BusRequest -> Addr
+busRequestToAddr req = case req of
+    BusReadRequest (ReadRequest addr _) -> addr
+    WriteReadRequest (WriteRequest addr _) -> addr
+
+mkBus :: (Addr -> Integer)
+      -> Vector numClients (BusClient inFlightTransactions)
+      -> Vector numServers (BusServer inFlightTransactions numClients)
+      -> Module Empty
+mkBus addrToServerTranslation clientVec serverVec = do
+    tagEngineByClientVec :: Vector numClients (TagEngine inFlightTransactions)
+    tagEngineByClientVec <- replicateM mkTagEngine
+
+    arbiterByServer :: Vector numServers (Arbiter_IFC numClients)
+    arbiterByServer <- replicateM (mkArbiter False)
+
+    addRules |>
+        rules
+            "placeholder rule": when True ==> do
+                let selectedServerArbiter = (select arbiterByServer 0)
+                mapM_ clientRequest selectedServerArbiter.clients
+
+            "connect request client 0": when True ==> do
+                let 
+                    clientIdx :: Integer = 0
+                    selectedClient ::(BusClient inFlightTransactions)
+                    selectedClient = (select clientVec clientIdx)
+                    selectedTagEngine = (select tagEngineByClientVec clientIdx)
+
+                tag <- selectedTagEngine.requestTag
+
+                busRequest      :: BusRequest
+                busRequest      <- selectedClient.dequeueRequest tag
+
+                let
+                    addr = busRequestToAddr busRequest
+                    targetServerIdx  = addrToServerTranslation addr
+                    targetServer  = (select serverVec targetServerIdx)
+                
+                -- targetServer
+                action {}
+
+    return $ interface Empty { }

bs/BusTypes.bs

@@ -1,12 +1,16 @@
 package BusTypes(
-    BusVal(..),
+    MkClientTagType,
-    BusError(..),
+    BusClient(..), BusServer(..),
-    TransactionSize(..),
+    BusRequest(..), BusResponse(..),
-    ReadRequest(..),
+    ReadRequest(..), ReadResponse(..), WriteRequest(..), WriteResponse(..),
-    WriteRequest(..)
+    BusVal(..), BusError(..), TransactionSize(..)
     ) where
 
 import Types
+import Vector
+import TagEngine
+
+type MkClientTagType a = (UInt (TLog a))
 
 data BusError
     = UnMapped
@@ -48,21 +52,47 @@ data BusResponse
   | BusWriteResponse    WriteResponse
   deriving (Bits, Eq, FShow)
 
-interface BusMaster =
+-- # BusClient.dequeueRequest
-  -- The Bus arbiter will call the Bus Master's request method
+--   * The Bus arbiter will call the Bus Client's request method if it is
-  -- if and only if it's the Bus Master's turn to make a request, and the Bus Master
+--     the Bus Client's turn to make a request, or if another client forfits
-  -- has a request to make.
+--     its turn.
-  -- It is up to the BusMaster to guard it's request method such that calling
+--   * The BusClient must guard its request method such that calling its
-  -- it's request method is only valid when the BusMaster has a request to make.
+--     request method is only valid when the BusClient has a request to make.
-  -- This has implications about for the implementor of BusMaster, namely, that it
+--   * This has implications about for the implementor of BusClient,
-  -- should hold its request until it's request method gets called.
+--     namely, that it should hold its request until it's request method
-  request  :: BusRequest
+--     gets called. The arbiter tags the request so that the client can
-  -- From the masters's perspective, the response should not be called by the
+--     later correctly correlate the response.
-  -- arbiter until the master is ready to accept the response. In other words,
+--   * Although the tag is technically passed in as an argument from the
-  -- response should be guarded by the client.
+--     arbiter to the client's request method, given that methods are
-  response :: BusResponse -> Action
+--     atomic in Bluespec, this is effectively equivalent to tagging the
+--     transaction from the client's perspective. Thus, the client must
+--     take care to appropiately store the tag.
+-- # BusClient.enqueueResponse
+--   * From the client's perspective, the response should not be called
+--     by the arbiter until the client is ready to accept the response.
+--     In other words, the response method should be guarded by the client.
+interface (BusClient :: # -> *) inFlightTransactions =
+  dequeueRequest  :: MkTagType inFlightTransactions
+                  -> ActionValue BusRequest
+  enqueueResponse :: (BusResponse, MkTagType inFlightTransactions)
+                  -> Action
 
-type Token = UInt 5
+-- # BusServer.dequeueResponse
-
+--   * If the arbiter is able to successfully call `dequeueResponse`, then
-a :: UInt 5
+--     the BusServer's internal logic must update such that it understands
-a = 3
+--     the response has been handed off.
+-- # BusServer.peekClientTagDestination
+--   * The arbiter looks at (peekClientTagDestination :: MkClientTagType) to
+--     determine whether or not it is currently safe whether to dequeue the
+--     response as well as where to route the response should it dequeue the
+--     response.
+--   * `peekClientTagDestination` should be guarded on whether or not there is
+--     a valid response available.
+interface (BusServer :: # -> # -> *) inFlightTransactions numClients =
+  enqueueRequest  :: (MkTagType inFlightTransactions, BusRequest)
+                  -> Action
+  dequeueResponse :: ActionValue (
+                      MkClientTagType numClients,
+                      BusResponse, transactionTagType
+                      )
+  peekClientTagDestination :: MkClientTagType numClients

bs/TagEngine.bs

@@ -1,4 +1,5 @@
 package TagEngine(
+    MkTagType,
     TagEngine(..),
     Util.BasicResult(..),
     mkTagEngine) where
@@ -9,11 +10,11 @@ import FIFO
 import FIFOF
 import SpecialFIFOs
 
-#define UIntLog2N(n) (UInt (TLog n))
+type MkTagType numTags = (UInt (TLog numTags))
 
 interface (TagEngine :: # -> *) numTags =
-    requestTag :: ActionValue UIntLog2N(numTags)
+    requestTag :: ActionValue (MkTagType numTags)
-    retireTag  :: UIntLog2N(numTags) -> Action
+    retireTag  :: (MkTagType numTags) -> Action
 
 -- The tag engine returns a tag that is unique for the duration of
 -- the lifetime of the tag. Useful when you need to tag transactions
@@ -44,7 +45,7 @@ mkTagEngine = do
     debugOnce <- mkReg True
 
     -- Rules
-    addRules $
+    addRules |>
         rules
             "debug_initial_state": when debugOnce ==> do
                 $display "tagUsage: " (fshow (readVReg tagUsage))
@@ -77,9 +78,9 @@ mkTagEngine = do
                     (Nothing, Nothing) -> action {}
 
     -- Interface
-    return $
+    return |>
         interface TagEngine
-            requestTag :: ActionValue UIntLog2N(numTags)
+            requestTag :: ActionValue (MkTagType numTags)
             requestTag = do
                 case initialTagDistributor of
                     Just 0 -> do
@@ -100,7 +101,7 @@ mkTagEngine = do
             -- so it is advisable that the caller of `retireTag` only attempt to retire valid tags.
             -- Internally, the tagEngine will keep a correct and consistent state since TagEngine
             -- validates tags before attempting to retire them.
-            retireTag :: UIntLog2N(numTags) -> Action
+            retireTag :: (MkTagType numTags) -> Action
             retireTag tag =
                 do
                     let