Fixed the disassembler to cope with cmpb.

src/disasm-ia32.cc

 // Copyright 2007-2008 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 904 matching lines @@
         { bool is_byte = *data == 0xC6;
           data++;
           AppendToBuffer("%s ", is_byte ? "mov_b" : "mov");
           data += PrintRightOperand(data);
           int32_t imm = is_byte ? *data : *reinterpret_cast<int32_t*>(data);
           AppendToBuffer(",0x%x", imm);
           data += is_byte ? 1 : 4;
         }
         break;
 
+      case 0x80:
+        { data++;
+          AppendToBuffer("%s ", "cmpb");
+          data += PrintRightOperand(data);
+          int32_t imm = *data;
+          AppendToBuffer(",0x%x", imm);
+          data++;
+        }
+        break;
+
       case 0x88:  // 8bit, fall through
       case 0x89:  // 32bit
         { bool is_byte = *data == 0x88;
           int mod, regop, rm;
           data++;
           get_modrm(*data, &mod, &regop, &rm);
           AppendToBuffer("%s ", is_byte ? "mov_b" : "mov");
           data += PrintRightOperand(data);
           AppendToBuffer(",%s", NameOfCPURegister(regop));
         }
@@ skipping 248 matching lines @@
     }
     for (int i = 6 - (pc - prev_pc); i >= 0; i--) {
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 
 }  // namespace disasm