diff --git a/tools/clang/unittests/HLSLExec/LongVectorOps.def b/tools/clang/unittests/HLSLExec/LongVectorOps.def
index 002b84a1f2..2a08b418e0 100644
--- a/tools/clang/unittests/HLSLExec/LongVectorOps.def
+++ b/tools/clang/unittests/HLSLExec/LongVectorOps.def
@@ -129,6 +129,8 @@ OP_DEFAULT_DEFINES(UnaryMath, Frexp, 1, "TestFrexp", "", " -DFUNC_FREXP=1")
 OP_DEFAULT(FloatSpecial, IsFinite, 1, "isfinite", "")
 OP_DEFAULT(FloatSpecial, IsInf, 1, "isinf", "")
 OP_DEFAULT(FloatSpecial, IsNan, 1, "isnan", "")
+OP(FloatSpecial, ModF, 1, "TestModF", "", " -DFUNC_TEST_MODF=1",
+   "LongVectorOp", Default1, Default2, Default3)
 
 OP_DEFAULT(BinaryComparison, LessThan, 2, "", "<")
 OP_DEFAULT(BinaryComparison, LessEqual, 2, "", "<=")
diff --git a/tools/clang/unittests/HLSLExec/LongVectors.cpp b/tools/clang/unittests/HLSLExec/LongVectors.cpp
index dce99fd647..be5c2053ae 100644
--- a/tools/clang/unittests/HLSLExec/LongVectors.cpp
+++ b/tools/clang/unittests/HLSLExec/LongVectors.cpp
@@ -103,6 +103,21 @@ static constexpr Operation Operations[] = {
 #include "LongVectorOps.def"
 };
 
+#define OP_WITH_OUT_PARAM(OPERATION, TYPE, IMPL)                               \
+  template <> struct ExpectedBuilder<OpType::OPERATION, TYPE> {                \
+    static std::vector<TYPE> buildExpected(Op<OpType::OPERATION, TYPE, 1>,     \
+                                           const InputSets<TYPE> &Inputs) {    \
+      DXASSERT_NOMSG(Inputs.size() == 1);                                      \
+      size_t VectorSize = Inputs[0].size();                                    \
+      std::vector<TYPE> Expected;                                              \
+      Expected.resize(VectorSize * 2);                                         \
+      for (size_t I = 0; I < VectorSize; ++I) {                                \
+        IMPL                                                                   \
+      }                                                                        \
+      return Expected;                                                         \
+    }                                                                          \
+  };
+
 constexpr const Operation &getOperation(OpType Op) {
   if (Op < OpType::NumOpTypes)
     return Operations[unsigned(Op)];
@@ -1015,41 +1030,21 @@ DEFAULT_OP_1(OpType::Log2, (std::log2(A)));
 // with special logic. Frexp is only supported for fp32 values.
 template <> struct Op<OpType::Frexp, float, 1> : DefaultValidation<float> {};
 
-template <> struct ExpectedBuilder<OpType::Frexp, float> {
-  static std::vector<float> buildExpected(Op<OpType::Frexp, float, 1> &,
-                                          const InputSets<float> &Inputs) {
-    DXASSERT_NOMSG(Inputs.size() == 1);
-
-    // Expected values size is doubled. In the first half we store the
-    // Mantissas and in the second half we store the Exponents. This way we
-    // can leverage the existing logic which verify expected values in a
-    // single vector. We just need to make sure that we organize the output in
-    // the same way in the shader and when we read it back.
+OP_WITH_OUT_PARAM(Frexp, float, {
+  int Exp = 0;
+  float Man = std::frexp(Inputs[0][I], &Exp);
 
-    size_t VectorSize = Inputs[0].size();
-
-    std::vector<float> Expected;
-    Expected.resize(VectorSize * 2);
-
-    for (size_t I = 0; I < VectorSize; ++I) {
-      int Exp = 0;
-      float Man = std::frexp(Inputs[0][I], &Exp);
+  // std::frexp returns a signed mantissa. But the HLSL implmentation
+  // returns an unsigned mantissa.
+  Man = std::abs(Man);
 
-      // std::frexp returns a signed mantissa. But the HLSL implmentation
-      // returns an unsigned mantissa.
-      Man = std::abs(Man);
+  Expected[I] = Man;
 
-      Expected[I] = Man;
-
-      // std::frexp returns the exponent as an int, but HLSL stores it as a
-      // float. However, the HLSL exponents fractional component is always 0.
-      // So it can conversion between float and int is safe.
-      Expected[I + VectorSize] = static_cast<float>(Exp);
-    }
-
-    return Expected;
-  }
-};
+  // std::frexp returns the exponent as an int, but HLSL stores it as a
+  // float. However, the HLSL exponents fractional component is always 0.
+  // So it can conversion between float and int is safe.
+  Expected[I + VectorSize] = static_cast<float>(Exp);
+});
 
 //
 // Binary Comparison
@@ -1236,6 +1231,23 @@ FLOAT_SPECIAL_OP(OpType::IsInf, (std::isinf(A)));
 FLOAT_SPECIAL_OP(OpType::IsNan, (std::isnan(A)));
 #undef FLOAT_SPECIAL_OP
 
+template <typename T> struct Op<OpType::ModF, T, 1> : DefaultValidation<T> {};
+
+OP_WITH_OUT_PARAM(ModF, float, {
+  float Exp = 0.0f;
+  float Man = std::modf(Inputs[0][I], &Exp);
+  Expected[I] = Man;
+  Expected[I + VectorSize] = Exp;
+});
+
+OP_WITH_OUT_PARAM(ModF, HLSLHalf_t, {
+  float Exp = 0.0f;
+  float Inp = float(Inputs[0][I]);
+  float Man = std::modf(Inp, &Exp);
+  Expected[I] = HLSLHalf_t(Man);
+  Expected[I + VectorSize] = HLSLHalf_t(Exp);
+});
+
 //
 // dispatchTest
 //
@@ -1772,10 +1784,12 @@ class DxilConf_SM69_Vectorized {
   HLK_TEST(IsFinite, HLSLHalf_t);
   HLK_TEST(IsInf, HLSLHalf_t);
   HLK_TEST(IsNan, HLSLHalf_t);
+  HLK_TEST(ModF, HLSLHalf_t);
 
   HLK_TEST(IsFinite, float);
   HLK_TEST(IsInf, float);
   HLK_TEST(IsNan, float);
+  HLK_TEST(ModF, float);
 
   // Binary Comparison
 
diff --git a/tools/clang/unittests/HLSLExec/ShaderOpArith.xml b/tools/clang/unittests/HLSLExec/ShaderOpArith.xml
index f89a87ca68..43fe5d6412 100644
--- a/tools/clang/unittests/HLSLExec/ShaderOpArith.xml
+++ b/tools/clang/unittests/HLSLExec/ShaderOpArith.xml
@@ -4112,6 +4112,20 @@ void MSMain(uint GID : SV_GroupIndex,
         }
         #endif
 
+        #ifdef FUNC_TEST_MODF
+        vector<OUT_TYPE, NUM> TestModF(vector<TYPE, NUM> Vector)
+        {
+          vector<OUT_TYPE, NUM> Mantissa;
+          vector<OUT_TYPE, NUM> Exponent;
+
+          Mantissa = modf(Vector, Exponent);
+
+          g_OutputVector.Store< vector<OUT_TYPE, NUM> >(sizeof(OUT_TYPE) * NUM, Exponent);
+
+          return Mantissa;
+        }
+        #endif
+
         #ifdef FUNC_SHUFFLE_VECTOR
         vector<OUT_TYPE, NUM> TestShuffleVector(TYPE Scalar)
         {