feat: 增加MOU用于处理fence相关指令

chisel/playground/src/Core.scala

@@ -95,10 +95,10 @@ class Core(implicit val config: CpuConfig) extends Module {
   decoderUnit.csr <> csr.decoderUnit
   decoderUnit.executeStage <> executeStage.decoderUnit
 
-  executeStage.ctrl.clear(0) := ctrl.memoryUnit.flush_req ||
+  executeStage.ctrl.clear(0) := ctrl.memoryUnit.flush ||
     ctrl.executeUnit.do_flush && ctrl.executeUnit.allow_to_go ||
     !ctrl.decoderUnit.allow_to_go && ctrl.executeUnit.allow_to_go
-  executeStage.ctrl.clear(1) := ctrl.memoryUnit.flush_req ||
+  executeStage.ctrl.clear(1) := ctrl.memoryUnit.flush ||
     (ctrl.executeUnit.do_flush && decoderUnit.executeStage.inst1.allow_to_go) ||
     (ctrl.executeUnit.allow_to_go && !decoderUnit.executeStage.inst1.allow_to_go)
   executeStage.ctrl.inst0_allow_to_go := ctrl.executeUnit.allow_to_go
@@ -137,8 +137,7 @@ class Core(implicit val config: CpuConfig) extends Module {
 
   io.debug <> writeBackUnit.debug
 
-  io.inst.fence := executeUnit.executeStage.inst0.info.fusel === FuType.mou &&
+  io.inst.fence     := false.B
-    executeUnit.executeStage.inst0.info.op === MOUOpType.fencei
   io.data.fence     := false.B
   io.inst.req       := !instFifo.full && !reset.asBool
   io.inst.cpu_ready := ctrl.fetchUnit.allow_to_go

chisel/playground/src/ctrl/Ctrl.scala

@@ -31,12 +31,12 @@ class Ctrl(implicit val config: CpuConfig) extends Module {
   io.decoderUnit.allow_to_go   := !(lw_stall || longest_stall)
   io.executeUnit.allow_to_go   := !longest_stall
   io.memoryUnit.allow_to_go    := !longest_stall
-  io.writeBackUnit.allow_to_go := !longest_stall || io.memoryUnit.flush_req
+  io.writeBackUnit.allow_to_go := !longest_stall || io.memoryUnit.flush
 
   io.fetchUnit.do_flush     := false.B
-  io.decoderUnit.do_flush   := io.memoryUnit.flush_req || io.executeUnit.branch || io.decoderUnit.branch
+  io.decoderUnit.do_flush   := io.memoryUnit.flush || io.executeUnit.flush || io.decoderUnit.branch
-  io.executeUnit.do_flush   := io.memoryUnit.flush_req || io.executeUnit.branch
+  io.executeUnit.do_flush   := io.memoryUnit.flush || io.executeUnit.flush
-  io.memoryUnit.do_flush    := io.memoryUnit.flush_req
+  io.memoryUnit.do_flush    := io.memoryUnit.flush
   io.writeBackUnit.do_flush := false.B
 
   io.executeUnit.fu.allow_to_go := io.memoryUnit.allow_to_go

chisel/playground/src/defines/Bundles.scala

@@ -85,7 +85,7 @@ class ExecuteFuCtrl extends Bundle {
 class ExecuteCtrl(implicit val config: CpuConfig) extends Bundle {
   val inst     = Output(Vec(config.fuNum, new MemRead()))
   val fu_stall = Output(Bool())
-  val branch   = Output(Bool())
+  val flush   = Output(Bool())
 
   val allow_to_go = Input(Bool())
   val do_flush    = Input(Bool())
@@ -94,7 +94,7 @@ class ExecuteCtrl(implicit val config: CpuConfig) extends Bundle {
 }
 
 class MemoryCtrl extends Bundle {
-  val flush_req = Output(Bool())
+  val flush = Output(Bool())
 
   val allow_to_go = Input(Bool())
   val do_flush    = Input(Bool())

chisel/playground/src/pipeline/execute/ExecuteUnit.scala

@@ -57,7 +57,7 @@ class ExecuteUnit(implicit val config: CpuConfig) extends Module {
   io.ctrl.inst(0).reg_waddr := io.executeStage.inst0.info.reg_waddr
   io.ctrl.inst(1).mem_wreg  := io.executeStage.inst1.info.mem_wreg
   io.ctrl.inst(1).reg_waddr := io.executeStage.inst1.info.reg_waddr
-  io.ctrl.branch            := io.fetchUnit.flush
+  io.ctrl.flush            := io.fetchUnit.flush
 
   io.csr.in.valid := is_csr.asUInt.orR
   io.csr.in.info := MuxCase(

chisel/playground/src/pipeline/execute/Fu.scala

@@ -38,6 +38,10 @@ class Fu(implicit val config: CpuConfig) extends Module {
 
   val alu        = Seq.fill(config.decoderNum)(Module(new Alu()))
   val branchCtrl = Module(new BranchCtrl()).io
+  val mou        = Module(new Mou()).io
+
+  mou.in.info := io.inst(0).info
+  mou.in.pc   := io.inst(0).pc
 
   branchCtrl.in.pc            := io.inst(0).pc
   branchCtrl.in.info          := io.inst(0).info
@@ -46,8 +50,10 @@ class Fu(implicit val config: CpuConfig) extends Module {
   branchCtrl.in.jump_regiser  := io.branch.jump_regiser
   branchCtrl.in.branch_target := io.branch.branch_target
   io.branch.branch            := branchCtrl.out.branch
-  io.branch.flush             := (branchCtrl.out.pred_fail || io.branch.jump_regiser)
+
-  io.branch.target            := branchCtrl.out.target
+  val branchCtrl_flush = (branchCtrl.out.pred_fail || io.branch.jump_regiser)
+  io.branch.flush  := branchCtrl_flush || mou.out.flush
+  io.branch.target := Mux(branchCtrl_flush, branchCtrl.out.target, mou.out.target)
 
   for (i <- 0 until (config.fuNum)) {
     alu(i).io.info              := io.inst(i).info

chisel/playground/src/pipeline/execute/Mou.scala

@@ -0,0 +1,31 @@
+package cpu.pipeline.execute
+
+import chisel3._
+import chisel3.util._
+import cpu.defines._
+import cpu.defines.Const._
+
+class Mou extends Module {
+  val io = IO(new Bundle {
+    val in = Input(new Bundle {
+      val info = new InstInfo()
+      val pc   = UInt(PC_WID.W)
+    })
+    val out = Output(new Bundle {
+      val flush  = Bool()
+      val target = UInt(PC_WID.W)
+    })
+  })
+
+  val valid   = io.in.info.valid
+  val fence_i = valid && io.in.info.fusel === FuType.mou && io.in.info.op === MOUOpType.fencei
+
+  // TODO:增加其他fence指令时只要在后面加就行
+  io.out.flush := fence_i
+  io.out.target := MuxCase(
+    io.in.pc + 4.U,
+    Seq(
+      fence_i -> (io.in.pc + 4.U)
+    )
+  )
+}

chisel/playground/src/pipeline/memory/MemoryUnit.scala

@@ -83,5 +83,5 @@ class MemoryUnit(implicit val config: CpuConfig) extends Module {
   io.fetchUnit.flush  := io.csr.out.flush && io.ctrl.allow_to_go
   io.fetchUnit.target := Mux(io.csr.out.flush, io.csr.out.flush_pc, io.writeBackStage.inst0.pc + 4.U)
 
-  io.ctrl.flush_req := io.fetchUnit.flush
+  io.ctrl.flush := io.fetchUnit.flush
 }