X64: Tweak code generation slightly.

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 634 matching lines @@
   switch (regop) {
     case 0:
       mnem = "add";
       break;
     case 1:
       mnem = "or";
       break;
     case 2:
       mnem = "adc";
       break;
+    case 3:
+      mnem = "sbb";
+      break;
     case 4:
       mnem = "and";
       break;
     case 5:
       mnem = "sub";
       break;
     case 6:
       mnem = "xor";
       break;
     case 7:
@@ skipping 830 matching lines @@
         if (reg == 0) {
           AppendToBuffer("nop");  // Common name for xchg rax,rax.
         } else {
           AppendToBuffer("xchg%c rax, %s",
                          operand_size_code(),
                          NameOfCPURegister(reg));
         }
         data++;
       }
         break;
-
+      case 0xB0:
+      case 0xB1:
+      case 0xB2:
+      case 0xB3:
+      case 0xB4:
+      case 0xB5:
+      case 0xB6:
+      case 0xB7:
+      case 0xB8:
+      case 0xB9:
+      case 0xBA:
+      case 0xBB:
+      case 0xBC:
+      case 0xBD:
+      case 0xBE:
+      case 0xBF: {
+        // mov reg8,imm8 or mov reg32,imm32
+        byte opcode = *data;
+        data++;
+        bool is_32bit = (opcode >= 0xB8);
+        int reg = (opcode & 0x7) | (rex_b() ? 8 : 0);
+        if (is_32bit) {
+          AppendToBuffer("mov%c %s, ",
+                         operand_size_code(),
+                         NameOfCPURegister(reg));
+          data += PrintImmediate(data, DOUBLEWORD_SIZE);
+        } else {
+          AppendToBuffer("movb %s, ",
+                         NameOfByteCPURegister(reg));
+          data += PrintImmediate(data, BYTE_SIZE);
+        }
+        break;
+      }
       case 0xFE: {
         data++;
         int mod, regop, rm;
         get_modrm(*data, &mod, &regop, &rm);
         if (regop == 1) {
           AppendToBuffer("decb ");
           data += PrintRightByteOperand(data);
         } else {
           UnimplementedInstruction();
         }
+        break;
       }
-        break;
-
       case 0x68:
         AppendToBuffer("push 0x%x", *reinterpret_cast<int32_t*>(data + 1));
         data += 5;
         break;
 
       case 0x6A:
         AppendToBuffer("push 0x%x", *reinterpret_cast<int8_t*>(data + 1));
         data += 2;
         break;
 
@@ skipping 214 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