fpu fix cmd / commit race condition

src/main/scala/vexriscv/TestsWorkspace.scala

@@ -121,11 +121,12 @@ object TestsWorkspace {
 //       cd buildroot-build/
 //       make O=$PWD  BR2_EXTERNAL=../buildroot-spinal-saxon  -C ../buildroot saxon_regression_defconfig
 
+      //make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no TRACE=yes REDO=1 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=no TRACE_START=565000000000ll SEED=45
+
+      //make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no TRACE=yes REDO=100 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=no TRACE_START=5600000000000ll SEED=45 STOP_ON_ERROR=ye
+
       // export IMAGES=/media/data/open/SaxonSoc/artyA7SmpUpdate/buildroot-regression/buildroot-build/images
-      // make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no LINUX_SOC_SMP=yes EMULATOR=$IMAGES/fw_jump.bin VMLINUX=$IMAGES/Image DTB=$IMAGES/linux.dtb RAMDISK=$IMAGES/rootfs.cpio  TRACE=ye REDO=1 DEBUG=ye WITH_USER_IO=no
+      // make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no LINUX_SOC_SMP=yes EMULATOR=$IMAGES/fw_jump.bin VMLINUX=$IMAGES/Image DTB=$IMAGES/linux.dtb RAMDISK=$IMAGES/rootfs.cpio  TRACE=yes REDO=1 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=no TRACE_START=565000000000ll SEED=45
-      // make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no LINUX_SOC_SMP=yes EMULATOR=$IMAGES/fw_jump.bin VMLINUX=$IMAGES/Image DTB=$IMAGES/linux.dtb RAMDISK=$IMAGES/rootfs.cpio  TRACE=yes REDO=1 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=yes TRACE_START=47000000000ll SEED=43
-      // make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no LINUX_SOC_SMP=yes EMULATOR=$IMAGES/fw_jump.bin VMLINUX=$IMAGES/Image DTB=$IMAGES/linux.dtb RAMDISK=$IMAGES/rootfs.cpio  TRACE=yes REDO=1 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=yes TRACE_START=47000000000ll SEED=45
-      //make clean all IBUS=CACHED IBUS_DATA_WIDTH=64 COMPRESSED=no DBUS=CACHED DBUS_LOAD_DATA_WIDTH=64 DBUS_STORE_DATA_WIDTH=64 LRSC=yes AMO=yes SUPERVISOR=yes DBUS_EXCLUSIVE=yes DBUS_INVALIDATE=yes MUL=yes DIV=yes RVF=yes RVD=yes DEBUG_PLUGIN=no LINUX_SOC_SMP=yes EMULATOR=$IMAGES/fw_jump.bin VMLINUX=$IMAGES/Image DTB=$IMAGES/linux.dtb RAMDISK=$IMAGES/rootfs.cpio  TRACE=yes REDO=1 DEBUG=ye WITH_USER_IO=no  FLOW_INFO=yes TRACE_START=565000000ll SEED=45
       val config = VexRiscvSmpClusterGen.vexRiscvConfig(
         hartId = 0,
         ioRange = _ (31 downto 28) === 0xF,
@@ -139,7 +140,8 @@ object TestsWorkspace {
         dCacheWays = 2,
         withFloat = true,
         withDouble = true,
-        externalFpu = false
+        externalFpu = false,
+        simHalt = true
       )
 
 

src/main/scala/vexriscv/demo/smp/VexRiscvSmpCluster.scala

@@ -167,7 +167,8 @@ object VexRiscvSmpClusterGen {
                      withSupervisor : Boolean = true,
                      withFloat : Boolean = false,
                      withDouble : Boolean = false,
-                     externalFpu : Boolean = true
+                     externalFpu : Boolean = true,
+                     simHalt : Boolean = false
                     ) = {
     assert(iCacheSize/iCacheWays <= 4096, "Instruction cache ways can't be bigger than 4096 bytes")
     assert(dCacheSize/dCacheWays <= 4096, "Data cache ways can't be bigger than 4096 bytes")
@@ -280,6 +281,7 @@ object VexRiscvSmpClusterGen {
 
     if(withFloat) config.plugins += new FpuPlugin(
       externalFpu = externalFpu,
+      simHalt = simHalt,
       p = FpuParameter(withDouble = withDouble)
     )
     config

src/main/scala/vexriscv/ip/fpu/FpuCore.scala

@@ -179,25 +179,10 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
     })
   }
 
-//  val completion = for(source <- 0 until portCount) yield new Area{
-//    def port = io.port(source)
-//    port.completion.flag.NV := False
-//    port.completion.flag.DZ := False
-//    port.completion.flag.OF := False
-//    port.completion.flag.UF := False
-//    port.completion.flag.NX := False
-//
-//    val increments = ArrayBuffer[Bool]()
-//
-//    afterElaboration{
-//      port.completion.count := increments.map(_.asUInt.resize(log2Up(increments.size + 1))).reduceBalancedTree(_ + _)
-//    }
-//  }
-
   val commitFork = new Area{
     val load, commit = Vec(Stream(FpuCommit(p)), portCount)
     for(i <- 0 until portCount){
-      val fork = new StreamFork(FpuCommit(p), 2)
+      val fork = new StreamFork(FpuCommit(p), 2, synchronous = true)
       fork.io.input << io.port(i).commit
       fork.io.outputs(0) >> load(i)
       fork.io.outputs(1).pipelined(m2s = true, s2m = true) >> commit(i) //Pipelining here is light, as it only use the flags of the payload
@@ -214,8 +199,9 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
   }
 
   class CommitArea(source : Int) extends Area{
+    val pending = new Tracker(4)
     val add, mul, div, sqrt, short = new Tracker(4)
-    val input = commitFork.commit(source).haltWhen(List(add, mul, div, sqrt, short).map(_.full).orR).toFlow
+    val input = commitFork.commit(source).haltWhen(List(add, mul, div, sqrt, short).map(_.full).orR || !pending.notEmpty).toFlow
 
     when(input.fire){
       add.inc   setWhen(List(FpuOpcode.ADD).map(input.opcode === _).orR)
@@ -224,6 +210,7 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
       sqrt.inc  setWhen(List(FpuOpcode.SQRT).map(input.opcode === _).orR)
       short.inc setWhen(List(FpuOpcode.SGNJ, FpuOpcode.MIN_MAX, FpuOpcode.FCVT_X_X).map(input.opcode === _).orR)
       rf.scoreboards(source).writes(input.rd) := input.write
+      pending.dec := True
     }
   }
 
@@ -237,7 +224,7 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
 
   val scheduler = for(portId <- 0 until portCount;
                       scoreboard = rf.scoreboards(portId)) yield new Area{
-    val input = io.port(portId).cmd.combStage()
+    val input = io.port(portId).cmd.pipelined(s2m = true)
     val useRs1, useRs2, useRs3, useRd = False
     switch(input.opcode){
       is(p.Opcode.LOAD)      { useRd := True }
@@ -265,7 +252,7 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
     val rfBusy = (rfHits, rfTargets).zipped.map(_ ^ _)
 
     val hits = (0 to 3).map(id => uses(id) && rfBusy(id))
-    val hazard = hits.orR || !rf.init.done
+    val hazard = hits.orR || !rf.init.done || commitLogic(portId).pending.full
     val output = input.haltWhen(hazard)
     when(input.valid && rf.init.done){
       scoreboard.targetWrite.address := input.rd
@@ -273,6 +260,7 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
     }
     when(output.fire && useRd){
       scoreboard.targetWrite.valid := True
+      commitLogic(portId).pending.inc := True
     }
   }
 
@@ -287,7 +275,7 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
   }
 
   val read = new Area{
-    val s0 = cmdArbiter.output.pipelined(m2s = true, s2m = true) //TODO may need to remove m2s for store latency
+    val s0 = cmdArbiter.output.pipelined() //TODO may need to remove m2s for store latency
     val s1 = s0.m2sPipe()
     val output = s1.swapPayload(RfReadOutput())
     val rs1Entry = rf.ram.readSync(s0.source @@ s0.rs1,enable = !output.isStall)
@@ -982,7 +970,6 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
 
       when(exp(exp.getWidth-3, 3 bits) >= 5) { output.exponent(p.internalExponentSize-2, 2 bits) := 3 }
 
-//      val flag = io.port(input.source).completion.flag
       when(forceNan) {
         output.setNanQuiet
         NV setWhen(infinitynan || input.rs1.isNanSignaling || input.rs2.isNanSignaling)
@@ -1479,8 +1466,6 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
       if (p.withDouble) output.format := input.format
       output.scrap := (mantissa(1) | mantissa(0) | roundingScrap)
 
-
-//      val flag = io.port(input.source).completion.flag
       output.NV := infinityNan || input.rs1.isNanSignaling || input.rs2.isNanSignaling
       output.DZ := False
       when(forceNan) {

src/main/scala/vexriscv/plugin/FpuPlugin.scala

@@ -10,6 +10,7 @@ import vexriscv.ip.fpu._
 import scala.collection.mutable.ArrayBuffer
 
 class FpuPlugin(externalFpu : Boolean = false,
+                simHalt : Boolean = false,
                 p : FpuParameter) extends Plugin[VexRiscv] with VexRiscvRegressionArg {
 
   object FPU_ENABLE extends Stageable(Bool())
@@ -222,10 +223,20 @@ class FpuPlugin(externalFpu : Boolean = false,
 
     val internal = (!externalFpu).generate (pipeline plug new Area{
       val fpu = FpuCore(1, p)
+      if(simHalt) {
+        val cmdHalt = in(Bool).setName("fpuCmdHalt").addAttribute(Verilator.public)
+        val commitHalt = in(Bool).setName("fpuCommitHalt").addAttribute(Verilator.public)
+        val rspHalt = in(Bool).setName("fpuRspHalt").addAttribute(Verilator.public)
+        fpu.io.port(0).cmd << port.cmd.haltWhen(cmdHalt)
+        fpu.io.port(0).commit << port.commit.haltWhen(commitHalt)
+        fpu.io.port(0).rsp.haltWhen(rspHalt) >> port.rsp
+        fpu.io.port(0).completion <> port.completion
+      } else {
         fpu.io.port(0).cmd << port.cmd
         fpu.io.port(0).commit << port.commit
         fpu.io.port(0).rsp >> port.rsp
         fpu.io.port(0).completion <> port.completion
+      }
     })
 
 

src/test/cpp/regression/main.cpp

@@ -1848,6 +1848,11 @@ public:
 				instanceCycles += 1;
 
 				for(SimElement* simElement : simElements) simElement->postCycle();
+				#ifdef RVF
+				top->fpuCmdHalt = VL_RANDOM_I(1);
+                top->fpuCommitHalt = VL_RANDOM_I(1);
+                top->fpuRspHalt = VL_RANDOM_I(1);
+                #endif
 
 
 
@@ -3815,10 +3820,10 @@ string riscvTestMemory[] = {
 
 
 string riscvTestFloat[] = {
+    "rv32uf-p-fmadd",
     "rv32uf-p-fadd",
     "rv32uf-p-fcmp",
     "rv32uf-p-fcvt_w",
-    "rv32uf-p-fmadd",
     "rv32uf-p-ldst",
     "rv32uf-p-recoding",
     "rv32uf-p-fclass",
@@ -3830,9 +3835,9 @@ string riscvTestFloat[] = {
 
 
 string riscvTestDouble[] = {
+    "rv32ud-p-fmadd",
     "rv32ud-p-fadd",
     "rv32ud-p-fcvt",
-    "rv32ud-p-fmadd",
     "rv32ud-p-recoding",
     "rv32ud-p-fclass",
     "rv32ud-p-fcvt_w",