From bdb5bc118051860ac8e1fed6a485205f5eb8e86c Mon Sep 17 00:00:00 2001
From: Dolu1990 <charles.papon.90@gmail.com>
Date: Fri, 22 Jan 2021 20:47:31 +0100
Subject: [PATCH] fpu div implement some special values handeling

---
 src/main/scala/vexriscv/ip/fpu/FpuCore.scala | 55 ++++++++++++++++----
 src/test/scala/vexriscv/ip/fpu/FpuTest.scala | 12 ++++-
 2 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/src/main/scala/vexriscv/ip/fpu/FpuCore.scala b/src/main/scala/vexriscv/ip/fpu/FpuCore.scala
index 606f8fc..33a792e 100644
--- a/src/main/scala/vexriscv/ip/fpu/FpuCore.scala
+++ b/src/main/scala/vexriscv/ip/fpu/FpuCore.scala
@@ -643,6 +643,14 @@ case class FpuCore( portCount : Int, p : FpuParameter) extends Component{
         decode.divSqrtToMul.rs2.sign := input.rs2.sign
         decode.divSqrtToMul.rs2.exponent := divExp.value + iterationValue.msb.asUInt
         decode.divSqrtToMul.rs2.mantissa := (iterationValue << 1).resized
+        val overflow = input.rs2.isZeroOrSubnormal
+        val nan = input.rs2.isNan || (input.rs1.isZeroOrSubnormal && input.rs2.isZeroOrSubnormal)
+
+        when(nan){
+          decode.divSqrtToMul.rs2.setNanQuiet
+        } elsewhen(overflow) {
+          decode.divSqrtToMul.rs2.setInfinity
+        }
         when(decode.divSqrtToMul.ready) {
           state := IDLE
           input.ready := True
@@ -806,17 +814,37 @@ object FpuSynthesisBench extends App{
     })
   }
 
+  class Shifter(width : Int) extends Rtl{
+    override def getName(): String = "shifter_" + width
+    override def getRtlPath(): String = getName() + ".v"
+    SpinalVerilog(new Component{
+      val a = in UInt(width bits)
+      val sel = in UInt(log2Up(width) bits)
+      val result = out(a >> sel)
+      setDefinitionName(Shifter.this.getName())
+    })
+  }
 
+  class Rotate(width : Int) extends Rtl{
+    override def getName(): String = "rotate_" + width
+    override def getRtlPath(): String = getName() + ".v"
+    SpinalVerilog(new Component{
+      val a = in UInt(width bits)
+      val sel = in UInt(log2Up(width) bits)
+      val result = out(a.rotateLeft(sel))
+      setDefinitionName(Rotate.this.getName())
+    })
+  }
 
-  val rtls = ArrayBuffer[Fpu]()
-  rtls += new Fpu(
-    "32",
-    portCount = 1,
-    FpuParameter(
-      internalMantissaSize = 23,
-      withDouble = false
-    )
-  )
+  val rtls = ArrayBuffer[Rtl]()
+//  rtls += new Fpu(
+//    "32",
+//    portCount = 1,
+//    FpuParameter(
+//      internalMantissaSize = 23,
+//      withDouble = false
+//    )
+//  )
 //  rtls += new Fpu(
 //    "64",
 //    portCount = 1,
@@ -826,6 +854,15 @@ object FpuSynthesisBench extends App{
 //    )
 //  )
 
+//  rtls += new Shifter(24)
+//  rtls += new Shifter(32)
+//  rtls += new Shifter(52)
+//  rtls += new Shifter(64)
+  rtls += new Rotate(24)
+  rtls += new Rotate(32)
+  rtls += new Rotate(52)
+  rtls += new Rotate(64)
+
   val targets = XilinxStdTargets()// ++ AlteraStdTargets()
 
 
diff --git a/src/test/scala/vexriscv/ip/fpu/FpuTest.scala b/src/test/scala/vexriscv/ip/fpu/FpuTest.scala
index b30b411..17dafff 100644
--- a/src/test/scala/vexriscv/ip/fpu/FpuTest.scala
+++ b/src/test/scala/vexriscv/ip/fpu/FpuTest.scala
@@ -393,7 +393,9 @@ class FpuTest extends FunSuite{
 
           div(rd,rs1,rs2)
           storeFloat(rd){v =>
-            val ref = a/b
+            val refUnclamped = a/b
+            val refClamped = clamp(clamp(a)/clamp(b))
+            val ref = refClamped
             val error = Math.abs(ref-v)/ref
             println(f"$a / $b = $v, $ref $error")
             assert(checkFloat(ref, v))
@@ -522,6 +524,14 @@ class FpuTest extends FunSuite{
         val fAll = fZeros ++ fSubnormals ++ fExpSmall ++ fExpNormal ++ fExpBig ++ fInfinity ++ fNan
 
 
+//        testDiv(0.0f, 1.2f )
+//        testDiv(1.2f, 0.0f )
+//        testDiv(0.0f, 0.0f )
+//        for(a <- fAll; _ <- 0 until 50) testDiv(a, randomFloat())
+//        for(a <- fAll; b <- fAll) testDiv(a, b)
+//        for(_ <- 0 until 1000) testDiv(randomFloat(), randomFloat())
+
+
 
         testMul(1.2f, 0f)
         for(a <- fAll; _ <- 0 until 50) testMul(a, randomFloat())