From fca8b8d7ebbf1cea3c721b4a3438bc3eccb8ee39 Mon Sep 17 00:00:00 2001
From: boykopovar <boykopovar@gmail.com>
Date: Wed, 5 Aug 2026 12:41:18 +0300
Subject: [PATCH] fix(code): add extrq decoding

---
 .../codegen/x86/X64OpcodeConstants.hpp        |  2 ++
 .../codegen/src/x86/X64InstructionDecoder.cpp | 22 +++++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/core/codegen/include/codegen/x86/X64OpcodeConstants.hpp b/core/codegen/include/codegen/x86/X64OpcodeConstants.hpp
index c88ef7cf9..69bc3598f 100644
--- a/core/codegen/include/codegen/x86/X64OpcodeConstants.hpp
+++ b/core/codegen/include/codegen/x86/X64OpcodeConstants.hpp
@@ -156,6 +156,8 @@ inline constexpr std::uint8_t TwoBytePextrw = 0xC5;
 inline constexpr std::uint8_t TwoByteShufpsImm8 = 0xC2;
 inline constexpr std::uint8_t TwoByteShufpdImm8 = 0xC6;
 inline constexpr std::uint8_t TwoByteGrp9 = 0xC7;
+inline constexpr std::uint8_t TwoByteExtrqInsertqImm8Imm8 = 0x78;
+inline constexpr std::uint8_t TwoByteExtrqInsertqModRm = 0x79;
 
 inline constexpr std::uint8_t VexNoModRmMin = 0x77;
 inline constexpr std::uint8_t VexNoModRmMax = 0x77;
diff --git a/core/codegen/src/x86/X64InstructionDecoder.cpp b/core/codegen/src/x86/X64InstructionDecoder.cpp
index 270513870..68860ec52 100644
--- a/core/codegen/src/x86/X64InstructionDecoder.cpp
+++ b/core/codegen/src/x86/X64InstructionDecoder.cpp
@@ -11,11 +11,18 @@ std::size_t X64InstructionDecoder::Decode(const std::uint8_t* data, std::size_t
     bool rexPresent = false;
     std::uint8_t rex = 0;
     bool operandSizeOverride = false;
+    bool repnePrefix = false;
 
     while (pos < available) {
         const std::uint8_t b = data[pos];
 
-        if (b == PrefixLock || b == PrefixRepne || b == PrefixRep ||
+        if (b == PrefixRepne) {
+            repnePrefix = true;
+            pos += 1;
+            continue;
+        }
+
+        if (b == PrefixLock || b == PrefixRep ||
             b == PrefixSegCs || b == PrefixSegSs || b == PrefixSegDs || b == PrefixSegEs ||
             b == PrefixSegFs || b == PrefixSegGs) {
             pos += 1;
@@ -196,7 +203,18 @@ std::size_t X64InstructionDecoder::Decode(const std::uint8_t* data, std::size_t
             immediateSize = ImmSize8;
         }
     } else {
-        if (opcode >= TwoByteJccRel32Min && opcode <= TwoByteJccRel32Max) {
+        if (opcode == TwoByteExtrqInsertqImm8Imm8) {
+            if (!operandSizeOverride && !repnePrefix) {
+                throw CodegenException("Unsupported 0F 78 opcode without SSE4A prefix");
+            }
+            hasModRm = true;
+            immediateSize = ImmSize16;
+        } else if (opcode == TwoByteExtrqInsertqModRm) {
+            if (!operandSizeOverride && !repnePrefix) {
+                throw CodegenException("Unsupported 0F 79 opcode without SSE4A prefix");
+            }
+            hasModRm = true;
+        } else if (opcode >= TwoByteJccRel32Min && opcode <= TwoByteJccRel32Max) {
             immediateSize = ImmSize32;
         } else if (opcode == TwoByteMovImm8ModRm) {
             hasModRm = true;