From ed8e0b8337539e4de4fab80883c381bf18da2a1d Mon Sep 17 00:00:00 2001
From: Yehowshua Immanuel <yehowshua@yehowshuaimmanuel.com>
Date: Tue, 25 Mar 2025 01:15:49 -0400
Subject: [PATCH] tag engine now allows from simultaneous retire and request -
 but had to use unsafe

---
 bs/TagEngine.bs             | 83 +++++++++++++++++++++++--------------
 bs/Tests/TagEngineTester.bs | 13 ++++--
 2 files changed, 62 insertions(+), 34 deletions(-)

diff --git a/bs/TagEngine.bs b/bs/TagEngine.bs
index 4d67898..134e2c8 100644
--- a/bs/TagEngine.bs
+++ b/bs/TagEngine.bs
@@ -34,12 +34,8 @@ mkTagEngine =
         methodRequestTagCalled :: PulseWire
         methodRequestTagCalled <- mkPulseWire
 
-
-        methodRetireTagCalled :: PulseWire
-        methodRetireTagCalled <- mkPulseWire
-
-        tagResponse :: RWire UIntLog2N(numTags)
-        tagResponse <- mkRWireSBR
+        methodRetireTagCalledValid :: RWire UIntLog2N(numTags)
+        methodRetireTagCalledValid <- mkUnsafeRWire
 
         debugOnce <- mkReg True
 
@@ -53,15 +49,48 @@ mkTagEngine =
                         $display "inUseVec : " (fshow |> readVReg inUseVec)
                         $display "stackPtr : " (fshow stackPtr)
                         debugOnce := False
-            <+>
-            rules
-                when (methodRequestTagCalled && methodRetireTagCalled) ==>
+
+                "update stack pointer": when True ==>
                     do
-                        $display "ho ho ho"
-                        -- let 
-                        --     nextStackPtr = 
-                        --         case of (methodRequestTagCalled, methodRetireTagCalled) of
-                        --             (True, True) -> 
+                        stackPtr := 
+                            case (methodRequestTagCalled, methodRetireTagCalledValid.wget) of
+                                (True, Just tag) -> stackPtr
+                                (True, Nothing) ->
+                                    case stackPtr of
+                                        Just 0 -> Nothing
+                                        Just sampledStackPtr -> Just |> sampledStackPtr - 1
+                                        Nothing -> Nothing
+                                (False, Just tag) ->
+                                    case stackPtr of
+                                        Just sampledStackPtr -> Just |> sampledStackPtr + 1
+                                        Nothing -> Nothing
+                                (False, Nothing) -> stackPtr
+
+                "update free stack": when True ==>
+                    do
+                        case (methodRequestTagCalled, methodRetireTagCalledValid.wget) of
+                            (True, Just tag) -> do action {}
+                            (True, Nothing) -> do action {}
+                            (False, Just tag) -> do
+                                case stackPtr of
+                                    Just sampledStackPtr -> do
+                                        (select freeStackVec (sampledStackPtr + 1)) := tag
+                                    Nothing -> do
+                                        (select freeStackVec 0) := tag
+                            (False, Nothing) -> do action {}
+
+                "update in use": when True ==>
+                    do
+                        case (methodRequestTagCalled, methodRetireTagCalledValid.wget) of
+                            (True, Just tag) -> do action {}
+                            (True, Nothing) ->
+                                case stackPtr of
+                                    Just sampledStackPtr -> do
+                                        (select inUseVec sampledStackPtr) := True
+                                    Nothing -> do action {}
+                            (False, Just tag) -> do
+                                (select inUseVec tag) := False
+                            (False, Nothing) -> do action {}
 
         counter <- mkReg(0 :: UIntLog2N(numTags))
         return $
@@ -71,23 +100,19 @@ mkTagEngine =
             requestTag =
                 do
                     methodRequestTagCalled.send
-                    stackPtr :=
-                        if sampledStackPtr == 0
-                            then Nothing
-                            else Just |> sampledStackPtr - 1
-                    (select inUseVec sampledStackPtr) := True
-                    return |> Just |> readReg (select freeStackVec sampledStackPtr)
-                when
-                    Just sampledStackPtr <- stackPtr
+                    case methodRetireTagCalledValid.wget of
+                        Just tag -> do
+                            return |> Just tag
+                        Nothing -> do
+                            return |> 
+                                case stackPtr of
+                                    Just sampledStackPtr -> 
+                                        Just |> readReg (select freeStackVec sampledStackPtr)
+                                    Nothing -> Nothing
 
-            -- retireTag isn't guarded so its up to external module to only attempt to
-            -- retire valid tags... At any rate, we can notify the requestor of failures
-            -- to retire tags - although the requestor can merely ignore this
-            -- notification.
             retireTag :: UIntLog2N(numTags) -> ActionValue BasicResult
             retireTag tag =
                 do
-                    methodRetireTagCalled.send
                     let
                         tagValid = tag < reifiedNumTags
                         tagInUse = readReg (select inUseVec tag)
@@ -97,9 +122,7 @@ mkTagEngine =
                                 Just n -> n + 1
                     if (tagValid && tagInUse)
                         then do
-                            (select inUseVec tag) := False
-                            (select freeStackVec nextStackPtrUint) := tag
-                            stackPtr := Just nextStackPtrUint
+                            methodRetireTagCalledValid.wset tag
                             return Success
                         else do
                             return Failure
diff --git a/bs/Tests/TagEngineTester.bs b/bs/Tests/TagEngineTester.bs
index 9cbab60..334b8d2 100644
--- a/bs/Tests/TagEngineTester.bs
+++ b/bs/Tests/TagEngineTester.bs
@@ -7,6 +7,7 @@ mkTagEngineTester :: Module Empty
 mkTagEngineTester = do
   tagEngine :: TagEngine 5 <- mkTagEngine
   count            :: Reg (UInt 4) <- mkReg 0;
+  runOnce :: Reg Bool <- mkReg False
 
   s :: ActionSeq
   s <- 
@@ -30,7 +31,11 @@ mkTagEngineTester = do
       |> do requestTagAction
       |> do requestTagAction
       |> do retireTagAction 3
-      |> do requestTagAction
+      |> do $display "BEGIN TRY SIMULTANEOUS RETIRE and REQUEST"
+      |> do 
+          retireTagAction 4
+          requestTagAction
+      |> do $display "END TRY SIMULTANEOUS RETIRE and REQUEST"
       |> do requestTagAction
       |> do retireTagAction 4
       |> do retireTagAction 4
@@ -42,7 +47,7 @@ mkTagEngineTester = do
 
   addRules $
     rules
-      "testIncrement": when (count < 10) ==>
+      "testIncrement": when (runOnce == False) ==>
         do
-          count := count + 1
-          s.start
\ No newline at end of file
+          s.start
+          runOnce := True
\ No newline at end of file