X64: Adding macro to load double from memory, and use SSE3 instruction if present.

src/x64/disasm-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1080 matching lines @@
       AppendToBuffer("movsd ");
       int mod, regop, rm;
       get_modrm(*current, &mod, &regop, &rm);
       if (opcode == 0x11) {
         current += PrintRightXMMOperand(current);
         AppendToBuffer(",%s", NameOfXMMRegister(regop));
       } else {
         AppendToBuffer("%s,", NameOfXMMRegister(regop));
         current += PrintRightXMMOperand(current);
       }
+    } else if (opcode == 0x12) {
+      // movddup xmm1, xmm2/m64
+      int mod, regop, rm;
+      get_modrm(*current, &mod, &regop, &rm);
+      AppendToBuffer("movddup %s,", NameOfXMMRegister(regop));
+      current += PrintRightXMMOperand(current);
     } else if (opcode == 0x2A) {
       // CVTSI2SD: integer to XMM double conversion.
       int mod, regop, rm;
       get_modrm(*current, &mod, &regop, &rm);
       AppendToBuffer("%sd %s,", mnemonic, NameOfXMMRegister(regop));
       current += PrintRightOperand(current);
     } else if (opcode == 0x2C) {
       // CVTTSD2SI:
       // Convert with truncation scalar double-precision FP to integer.
       int mod, regop, rm;
@@ skipping 712 matching lines @@
     for (int i = 6 - static_cast<int>(pc - prev_pc); i >= 0; i--) {
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_X64