Added the bsf instruction to the disassembler of x64 and ia32.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1418183002

Cr-Commit-Position: refs/heads/master@{#31487}

src/ia32/disasm-ia32.cc

@@ -1231,6 +1231,8 @@ static const char* F0Mnem(byte f0byte) {
     case 0xAD: return "shrd";
     case 0xAC: return "shrd";  // 3-operand version.
     case 0xAB: return "bts";
+    case 0xBC:
+      return "bsf";
     case 0xBD: return "bsr";
     default: return NULL;
   }
@@ -1482,6 +1484,12 @@ int DisassemblerIA32::InstructionDecode(v8::internal::Vector<char> out_buffer,
             } else {
               AppendToBuffer(",%s,cl", NameOfCPURegister(regop));
             }
+          } else if (f0byte == 0xBC) {
+            data += 2;
+            int mod, regop, rm;
+            get_modrm(*data, &mod, &regop, &rm);
+            AppendToBuffer("%s %s,", f0mnem, NameOfCPURegister(regop));
+            data += PrintRightOperand(data);
           } else if (f0byte == 0xBD) {
             data += 2;
             int mod, regop, rm;

src/x64/disasm-x64.cc

@@ -1824,6 +1824,12 @@ int DisassemblerX64::TwoByteOpcodeInstruction(byte* data) {
     } else {
       AppendToBuffer(",%s,cl", NameOfCPURegister(regop));
     }
+  } else if (opcode == 0xBC) {
+    AppendToBuffer("%s%c ", mnemonic, operand_size_code());
+    int mod, regop, rm;
+    get_modrm(*current, &mod, &regop, &rm);
+    AppendToBuffer("%s,", NameOfCPURegister(regop));
+    current += PrintRightOperand(current);
   } else if (opcode == 0xBD) {
     AppendToBuffer("%s%c ", mnemonic, operand_size_code());
     int mod, regop, rm;
@@ -1878,6 +1884,8 @@ const char* DisassemblerX64::TwoByteMnemonic(byte opcode) {
       return "movzxb";
     case 0xB7:
       return "movzxw";
+    case 0xBC:
+      return "bsf";
     case 0xBD:
       return "bsr";
     case 0xBE: