[MIPS] Use break instruction as NACL_HALT for MIPS.

src/trusted/validator_mips/inst_classes.h

 /*
  * Copyright 2012 The Native Client Authors.  All rights reserved.
  * Use of this source code is governed by a BSD-style license that can
  * be found in the LICENSE file.
  * Copyright 2012, Google Inc.
  */
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_INST_CLASSES_H
 #define NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_INST_CLASSES_H
 
@@ skipping 41 matching lines @@
  * This is an abstract base class intended to be overridden with the details of
  * particular instruction-classes.
  *
  * ClassDecoders should be stateless, and should provide a no-arg constructor
  * for use by the generated decoder.
  */
 class ClassDecoder {
  public:
   /*
    * Checks how safe this instruction is, in isolation.
-   * This will detect any violation in the Mips spec -- undefined encodings,
+   * This will detect any violation in the MIPS spec -- undefined encodings,
    * use of registers that are unpredictable -- and the most basic constraints
    * in our SFI model.  Because ClassDecoders are referentially-transparent and
    * cannot touch global state, this will not check things that may vary with
    * ABI version.
    *
    * The most positive result this can return is called MAY_BE_SAFE because it
    * is necessary, but not sufficient: the validator has the final say.
    */
   virtual SafetyLevel safety(const Instruction instr) const = 0;
 
@@ skipping 89 matching lines @@
     return kRegisterNone;
   }
 
 
  protected:
   ClassDecoder() {}
   virtual ~ClassDecoder() {}
 };
 
 /*
- * Current Mips NaCl halt (jr $zero).
+ * Current MIPS NaCl halt (break).
  */
 class NaClHalt : public ClassDecoder {
   public:
     virtual ~NaClHalt() {}
     virtual SafetyLevel safety(const Instruction instr) const {
       UNREFERENCED_PARAMETER(instr);
       return MAY_BE_SAFE;
     }
 };
 
@@ skipping 246 matching lines @@
  public:
   virtual ~Unrecognized() {}
   virtual SafetyLevel safety(const Instruction instr) const {
     UNREFERENCED_PARAMETER(instr);
     return FORBIDDEN;
   }
 };
 }  // namespace
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_INST_CLASSES_H