diff --git a/core/relinker/codegen/include/codegen/x86/X64OpcodeConstants.hpp b/core/relinker/codegen/include/codegen/x86/X64OpcodeConstants.hpp
index 889d0c447..7a9a14a36 100644
--- a/core/relinker/codegen/include/codegen/x86/X64OpcodeConstants.hpp
+++ b/core/relinker/codegen/include/codegen/x86/X64OpcodeConstants.hpp
@@ -170,6 +170,7 @@ inline constexpr std::uint8_t TwoByteGrp6 = 0x00;
 inline constexpr std::uint8_t TwoByteLar = 0x02;
 inline constexpr std::uint8_t TwoByteLsl = 0x03;
 inline constexpr std::uint8_t TwoBytePrefetchw = 0x0D;
+inline constexpr std::uint8_t TwoByte3DNow = 0x0F;
 inline constexpr std::uint8_t TwoByteMovCrDrMin = 0x20;
 inline constexpr std::uint8_t TwoByteMovCrDrMax = 0x23;
 inline constexpr std::uint8_t TwoBytePopcnt = 0xB8;
diff --git a/core/relinker/codegen/src/x86/X64InstructionDecoder.cpp b/core/relinker/codegen/src/x86/X64InstructionDecoder.cpp
index b894332bd..ab5785a01 100644
--- a/core/relinker/codegen/src/x86/X64InstructionDecoder.cpp
+++ b/core/relinker/codegen/src/x86/X64InstructionDecoder.cpp
@@ -242,7 +242,7 @@ std::size_t X64InstructionDecoder::Decode(const std::uint8_t* data, std::size_t
             hasModRm = true;
         } else if (opcode >= TwoByteJccRel32Min && opcode <= TwoByteJccRel32Max) {
             immediateSize = ImmSize32;
-        } else if (opcode == TwoByteMovImm8ModRm) {
+        } else if (opcode == TwoByteMovImm8ModRm || opcode == TwoByte3DNow) {
             hasModRm = true;
             immediateSize = ImmSize8;
         } else if (opcode >= TwoByteShiftImm8Min && opcode <= TwoByteShiftImm8Max) {
diff --git a/core/relinker/codegen/tests/DecoderLengthCases.hpp b/core/relinker/codegen/tests/DecoderLengthCases.hpp
index 561f3a64e..10747c9a6 100644
--- a/core/relinker/codegen/tests/DecoderLengthCases.hpp
+++ b/core/relinker/codegen/tests/DecoderLengthCases.hpp
@@ -33,6 +33,12 @@ inline constexpr DecoderLengthCase kDecoderLengthCases[] = {
     {"0f0b", 2},
     {"0f0d846511223344", 8},
     {"0f0e", 2},
+    {"0f0fc196", 4},
+    {"0f0f08b7", 4},
+    {"0f0f4f80b4", 5},
+    {"0f0f846511223344b4", 9},
+    {"0f0f0d11223344a6", 8},
+    {"410f0f1c24bf", 6},
     {"0f10846511223344", 8},
     {"0f11846511223344", 8},
     {"0f12846511223344", 8},