Merge branch 'dev-rs' into dev-prefetcher

src/main/scala/xiangshan/backend/issue/ReservationStationNew.scala

@@ -143,32 +143,31 @@ class ReservationStationCtrl
   val issFire = Wire(Bool())
   val moveMask = WireInit(0.U(iqSize.W))
   val selectMask = WireInit(VecInit((0 until iqSize).map(i => readyIdxQue(i))))
-  val haveBubble = Wire(Bool())
   // val selIdx = ParallelMux(selectMask zip idxQueue) // NOTE: the idx in the idxQueue
   val (selPtr, haveReady) = PriorityEncoderWithFlag(selectMask) // NOTE: the idx of idxQueue
   val selIdx = idxQueue(selPtr)
   val selIdxReg = RegNext(selIdx) // NOTE: may dup with other signal, fix it later
   val redSel = redVec(selIdx)
-  val selValid = !redSel && haveReady && !haveBubble
+  val selValid = !redSel && haveReady
   val selReg = RegNext(selValid)
-  val selPtrReg = RegNext(Mux(moveMask(selPtr), selPtr-1.U, selPtr)) // TODO: deal with the long latency
+  val selPtrReg = RegNext(Mux(moveMask(selPtr), selPtr-1.U, selPtr))
 
   // sel bubble
   val bubMask = WireInit(VecInit((0 until iqSize).map(i => emptyIdxQue(i))))
   // val bubIdx = ParallelMux(bubMask zip idxQueue) // NOTE: the idx in the idxQueue
   val (bubPtr, findBubble) = PriorityEncoderWithFlag(bubMask) // NOTE: the idx of the idxQueue
-  haveBubble := findBubble && (bubPtr < tailPtr.asUInt)
+  val haveBubble = findBubble && (bubPtr < tailPtr.asUInt)
   val bubIdx = idxQueue(bubPtr)
   val bubIdxReg = RegNext(bubIdx) // NOTE: may dup with other signal, fix it later
-  val bubValid = haveBubble
+  val bubValid = haveBubble && (if (feedback) true.B else !selValid)
   val bubReg = RegNext(bubValid)
-  val bubPtrReg = RegNext(Mux(moveMask(bubPtr), bubPtr-1.U, bubPtr)) // TODO: deal with the long latency
+  val bubPtrReg = RegNext(Mux(moveMask(bubPtr), bubPtr-1.U, bubPtr))
 
   // deq
-  // TODO: mem's rs will issue but not deq( the bub), so just divide issue and deq
-  // TODO: when need feadback, only deq when becomes bubble
-  val dequeue = if (feedback) bubReg else bubReg || issFire
-  val deqPtr = Mux(bubReg, bubPtrReg, selPtrReg)
+  val dequeue = if (feedback) bubReg
+                else          bubReg || issFire
+  val deqPtr =  if (feedback) bubPtrReg
+                else Mux(selReg, selPtrReg, bubPtrReg)
   moveMask := {
     (Fill(iqSize, 1.U(1.W)) << deqPtr)(iqSize-1, 0)
   } & Fill(iqSize, dequeue)
@@ -184,32 +183,18 @@ class ReservationStationCtrl
   }
   when (selValid) {
     stateQueue(selIdx) := s_selected
-    // TODO: may have long latency
   }
-  when (haveBubble) {
+  when (bubValid) {
     stateQueue(bubIdx) := s_bubble
   }
 
-  when (stateQueue(selIdxReg) === s_selected) {
-    when (io.data.fuReady) {
-      if (feedback) {
-        stateQueue(selIdxReg) := s_wait
-      } else {
-        stateQueue(selIdxReg) := s_idle
-      }
-    }.otherwise { stateQueue(selIdxReg) := s_valid } // fu is not ready and re-select next cycle
-  }
-  when (stateQueue(bubIdxReg) === s_bubble) {
-    stateQueue(bubIdxReg) := s_idle // move the bubble to the last positon
-  }
-
   // redirect and feedback && wakeup
   for (i <- 0 until iqSize) {
     // replay
     val cnt = cntQueue(i)
     when (stateQueue(i) === s_replay) {
+      cnt := cnt - 1.U
       when (cnt === 0.U) { stateQueue(i) := s_valid }
-      .otherwise { cnt := cnt - 1.U }
     }
     // feedback
     when (fbMatchVec(i)) {
@@ -224,6 +209,20 @@ class ReservationStationCtrl
         XSDebug(p"srcHit: i:${i.U} j:${j.U} src:${srcQueue(i)(j)}\n")
       }
     }
+    // mask last selectet slot and deal with the mask
+    // TODO: state queu change may have long 'when' chain -> long latency
+    when (stateQueue(i) === s_selected) {
+      when (io.data.fuReady) {
+        if (feedback) {
+          stateQueue(i) := s_wait
+        }  else {
+          stateQueue(i) := s_idle
+        }
+      }.otherwise { stateQueue(i) := s_valid }
+    }
+    when (stateQueue(i) === s_bubble) {
+      stateQueue(i) := s_idle
+    }
     // redirect
     when (redVec(i) && stateQueue(i) =/= s_idle) {
       stateQueue(i) := s_idle
@@ -296,7 +295,7 @@ class ReservationStationCtrl
   XSDebug(print, p"moveMask:${Binary(moveMask)} selMask:${Binary(selectMask.asUInt)} bubMask:${Binary(bubMask.asUInt)}\n")
   XSDebug(print, p"selIdxWire:${selPtr} haveReady:${haveReady} redSel:${redSel}" +
     p"selV:${selValid} selReg:${selReg} selPtrReg:${selPtrReg} selIdx:${selIdx} selIdxReg:${selIdxReg}\n")
-  XSDebug(print, p"haveBub:${haveBubble} bubPtr:${bubPtr} findBub:${findBubble} " +
+  XSDebug(print, p"bubValid:${bubValid} haveBub:${haveBubble} bubPtr:${bubPtr} findBub:${findBubble} " +
     p"bubReg:${bubReg} bubPtrReg:${bubPtrReg} bubIdx:${bubIdx} bubIdxReg:${bubIdxReg}\n")
   XSDebug(print, p"issValid:${issValid} issueFire:${issFire} dequeue:${dequeue} deqPtr:${deqPtr}\n")
   XSDebug(p" :Idx|v|r|s |cnt|s1:s2:s3\n")