diff --git a/llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h b/llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h
index 4a1cd7f02dbb130bf097299a0a7cba8834364322..93fca923e5a167f85fecf466743e4766196fa2bf 100644
--- a/llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h
+++ b/llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h
@@ -117,6 +117,9 @@ protected: // Can only create subclasses.
   const MCSubtargetInfo *STI;
 
 public:
+  // save Keystone syntax
+  int KsSyntax;
+
   ~MCTargetAsmParser() override;
 
   const MCSubtargetInfo &getSTI() const;
diff --git a/llvm/keystone/ks.cpp b/llvm/keystone/ks.cpp
index 9b4804b54512734ded7149492219b377a4b74c2e..6195c0b729d46dd8947d2fef59737761c64e3f21 100644
--- a/llvm/keystone/ks.cpp
+++ b/llvm/keystone/ks.cpp
@@ -413,6 +413,7 @@ ks_err ks_option(ks_engine *ks, ks_opt_type type, size_t value)
             switch(value) {
                 default:
                     return KS_ERR_OPT_INVALID;
+                case KS_OPT_SYNTAX_NASM:
                 case KS_OPT_SYNTAX_INTEL:
                     ks->syntax = (ks_opt_value)value;
                     ks->MAI->setAssemblerDialect(1);
@@ -473,6 +474,7 @@ int ks_asm(ks_engine *ks,
 
     MCAsmParser *Parser = createMCAsmParser(ks->SrcMgr, *Ctx, *Streamer, *ks->MAI);
     MCTargetAsmParser *TAP = ks->TheTarget->createMCAsmParser(*ks->STI, *Parser, *ks->MCII, ks->MCOptions);
+    TAP->KsSyntax = ks->syntax;
 
     Parser->setTargetParser(*TAP);
 
diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index fe00515009a6463c81ca4069abacbf59035cafa8..12783a823ad0a7293da166e25b053b8c15fd0edc 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1805,9 +1805,16 @@ std::unique_ptr<X86Operand> X86AsmParser::ParseIntelOperand() {
   unsigned Size = getIntelMemOperandSize(Tok.getString());
   if (Size) {
     Parser.Lex(); // Eat operand size (e.g., byte, word).
-    if (Tok.getString() != "PTR" && Tok.getString() != "ptr")
-      return ErrorOperand(Tok.getLoc(), "Expected 'PTR' or 'ptr' token!");
-    Parser.Lex(); // Eat ptr.
+    if (KsSyntax == KS_OPT_SYNTAX_NASM) {
+        // Nasm do not accept 'PTR' in memory operands
+        if (Tok.getString() == "PTR" && Tok.getString() == "ptr")
+            return ErrorOperand(Tok.getLoc(), "Do not expected 'PTR' or 'ptr' token!");
+    } else {
+        // LLVM requires 'PTR' in memory operand
+        if (Tok.getString() != "PTR" && Tok.getString() != "ptr")
+            return ErrorOperand(Tok.getLoc(), "Expected 'PTR' or 'ptr' token!");
+        Parser.Lex(); // Eat ptr.
+    }
     PtrInOperand = true;
   }
   Start = Tok.getLoc();