diff --git a/MCInst.h b/MCInst.h
index 6a988b64..36c838e3 100644
--- a/MCInst.h
+++ b/MCInst.h
@@ -150,6 +150,7 @@ struct MCInst {
 	// A prefix byte gets value 0 when irrelevant.
 	// This is copied from cs_x86 struct
 	uint8_t x86_prefix[5];
+	bool x86_lock_rep;	// does this X86 insn contain LOCK/REP prefix?
 };
 
 void MCInst_Init(MCInst *inst);
diff --git a/arch/X86/X86Disassembler.c b/arch/X86/X86Disassembler.c
index 8a3311b1..f3285d5b 100644
--- a/arch/X86/X86Disassembler.c
+++ b/arch/X86/X86Disassembler.c
@@ -800,6 +800,10 @@ bool X86_getInstruction(csh ud, const uint8_t *code, size_t code_len,
 				}
 			}
 
+			if (insn.prefixPresent[0xf0] || insn.prefixPresent[0xf2] ||
+					insn.prefixPresent[0xf3])
+				instr->x86_lock_rep = true;
+
 			// save immediate size to print immediate properly
 			instr->x86_imm_size = insn.immediateSize;
 		}
diff --git a/arch/X86/X86GenAsmWriter.inc b/arch/X86/X86GenAsmWriter.inc
index 5d2745f4..4715e16b 100644
--- a/arch/X86/X86GenAsmWriter.inc
+++ b/arch/X86/X86GenAsmWriter.inc
@@ -12498,25 +12498,8 @@ static void printInstruction(MCInst *MI, SStream *O, MCRegisterInfo *MRI)
   uint64_t Bits = (Bits2 << 32) | Bits1;
   // assert(Bits != 0 && "Cannot print this instruction.");
 #ifndef CAPSTONE_DIET
-  int i;
-
-  for(i = 0; i < ARR_SIZE(MI->x86_prefix); i++) {
-    switch(MI->x86_prefix[i]) {
-      default:
-        break;
-      case 0xf0:
-        SStream_concat(O, "lock|");
-        break;
-      case 0xf2:
-        SStream_concat(O, "repne|");
-        break;
-      case 0xf3:
-        SStream_concat(O, "rep|");
-        break;
-    }
-  }
-
-  SStream_concat(O, "%s", AsmStrs+(Bits & 16383)-1);
+  if (!X86_lockrep(MI, O))
+    SStream_concat(O, "%s", AsmStrs+(Bits & 16383)-1);
 #endif
 
 
diff --git a/arch/X86/X86GenAsmWriter1.inc b/arch/X86/X86GenAsmWriter1.inc
index 2b8c3b73..0edafc9e 100644
--- a/arch/X86/X86GenAsmWriter1.inc
+++ b/arch/X86/X86GenAsmWriter1.inc
@@ -12202,24 +12202,8 @@ static void printInstruction(MCInst *MI, SStream *O, MCRegisterInfo *MRI)
   uint64_t Bits = (Bits2 << 32) | Bits1;
   // assert(Bits != 0 && "Cannot print this instruction.");
 #ifndef CAPSTONE_DIET
-  int i;
-  for(i = 0; i < ARR_SIZE(MI->x86_prefix); i++) {
-    switch(MI->x86_prefix[i]) {
-      default:
-        break;
-      case 0xf0:
-        SStream_concat(O, "lock|");
-        break;
-      case 0xf2:
-        SStream_concat(O, "repne|");
-        break;
-      case 0xf3:
-        SStream_concat(O, "rep|");
-        break;
-    }
-  }
-
-  SStream_concat(O, "%s", AsmStrs+(Bits & 16383)-1);
+  if (!X86_lockrep(MI, O))
+    SStream_concat(O, "%s", AsmStrs+(Bits & 16383)-1);
 #endif
 
 
diff --git a/arch/X86/X86Mapping.c b/arch/X86/X86Mapping.c
index 92a7c176..ea360113 100644
--- a/arch/X86/X86Mapping.c
+++ b/arch/X86/X86Mapping.c
@@ -41706,3 +41706,44 @@ x86_reg X86_insn_reg(unsigned int id)
 	return 0;
 }
 
+#ifndef CAPSTONE_DIET
+// return true if we patch the mnemonic
+bool X86_lockrep(MCInst *MI, SStream *O)
+{
+	int i;
+
+	if (MI->x86_lock_rep) {
+		for(i = 0; i < ARR_SIZE(MI->x86_prefix); i++) {
+			switch(MI->x86_prefix[i]) {
+				default:
+					break;
+				case 0xf0:
+					SStream_concat(O, "lock|");
+					break;
+				case 0xf2:
+					if (MI->Opcode == X86_MULPDrr) {
+						MI->Opcode = X86_MULSDrr;
+						SStream_concat(O, "mulsd\t");
+						MI->x86_prefix[i] = 0;
+						// notify that we already patched mnemonic
+						return true;
+					} else
+						SStream_concat(O, "repne|");
+					break;
+				case 0xf3:
+					if (MI->Opcode == X86_MULPDrr) {
+						MI->Opcode = X86_MULSSrr;
+						SStream_concat(O, "mulss\t");
+						MI->x86_prefix[i] = 0;
+						// notify that we already patched mnemonic
+						return true;
+					} else
+						SStream_concat(O, "rep|");
+					break;
+			}
+		}
+	}
+
+	return false;
+}
+#endif
diff --git a/arch/X86/X86Mapping.h b/arch/X86/X86Mapping.h
index 7b8848cb..1c7a22c9 100644
--- a/arch/X86/X86Mapping.h
+++ b/arch/X86/X86Mapping.h
@@ -39,4 +39,10 @@ x86_reg X86_insn_reg(unsigned int id);
 
 extern uint64_t arch_masks[9];
 
+#ifndef CAPSTONE_DIET
+// handle LOCK/REP/REPNE prefixes
+// return True if we patch mnemonic, like in MULPD case
+bool X86_lockrep(MCInst *MI, SStream *O);
+#endif
+
 #endif