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 /*

  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

  * Copyright 2007, 2008, 2009 Red Hat, Inc.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #ifndef CPU_ZERO_VM_BYTES_ZERO_HPP

 #define CPU_ZERO_VM_BYTES_ZERO_HPP

 #include "memory/allocation.hpp"

 typedef union unaligned {

   u4 u;

   u2 us;

   u8 ul;

 } __attribute__((packed)) unaligned;

 class Bytes: AllStatic {

  public:

   // Returns true if the byte ordering used by Java is different

   // from the native byte ordering of the underlying machine.

   static inline bool is_Java_byte_ordering_different() {

 #ifdef VM_LITTLE_ENDIAN

     return true;

 #else

     return false;

 #endif

   }

   // Efficient reading and writing of unaligned unsigned data in

   // platform-specific byte ordering.

   static inline u2 get_native_u2(address p){

     unaligned *up = (unaligned *) p;

     return up->us;

   }

   static inline u4 get_native_u4(address p) {

     unaligned *up = (unaligned *) p;

     return up->u;

   }

   static inline u8 get_native_u8(address p) {

     unaligned *up = (unaligned *) p;

     return up->ul;

   }

   static inline void put_native_u2(address p, u2 x) {

     unaligned *up = (unaligned *) p;

     up->us = x;

   }

   static inline void put_native_u4(address p, u4 x) {

     unaligned *up = (unaligned *) p;

     up->u = x;

   }

   static inline void put_native_u8(address p, u8 x) {

     unaligned *up = (unaligned *) p;

     up->ul = x;

   }

   // Efficient reading and writing of unaligned unsigned data in Java

   // byte ordering (i.e. big-endian ordering).

 #ifdef VM_LITTLE_ENDIAN

   // Byte-order reversal is needed

   static inline u2 get_Java_u2(address p) {

     return (u2(p[0]) << 8) |

            (u2(p[1])     );

   }

   static inline u4 get_Java_u4(address p) {

     return (u4(p[0]) << 24) |

            (u4(p[1]) << 16) |

            (u4(p[2]) <<  8) |

            (u4(p[3])      );

   }

   static inline u8 get_Java_u8(address p) {

     u4 hi, lo;

     hi = (u4(p[0]) << 24) |

          (u4(p[1]) << 16) |

          (u4(p[2]) <<  8) |

          (u4(p[3])      );

     lo = (u4(p[4]) << 24) |

          (u4(p[5]) << 16) |

          (u4(p[6]) <<  8) |

          (u4(p[7])      );

     return u8(lo) | (u8(hi) << 32);

   }

   static inline void put_Java_u2(address p, u2 x) {

     p[0] = x >> 8;

     p[1] = x;

   }

   static inline void put_Java_u4(address p, u4 x) {

     p[0] = x >> 24;

     p[1] = x >> 16;

     p[2] = x >> 8;

     p[3] = x;

   }

   static inline void put_Java_u8(address p, u8 x) {

     u4 hi, lo;

     lo = x;

     hi = x >> 32;

     p[0] = hi >> 24;

     p[1] = hi >> 16;

     p[2] = hi >> 8;

     p[3] = hi;

     p[4] = lo >> 24;

     p[5] = lo >> 16;

     p[6] = lo >> 8;

     p[7] = lo;

   }

   // Efficient swapping of byte ordering

   static inline u2 swap_u2(u2 x);

   static inline u4 swap_u4(u4 x);

   static inline u8 swap_u8(u8 x);

 #else

   // No byte-order reversal is needed

   static inline u2 get_Java_u2(address p) {

     return get_native_u2(p);

   }

   static inline u4 get_Java_u4(address p) {

     return get_native_u4(p);

   }

   static inline u8 get_Java_u8(address p) {

     return get_native_u8(p);

   }

   static inline void put_Java_u2(address p, u2 x) {

     put_native_u2(p, x);

   }

   static inline void put_Java_u4(address p, u4 x) {

     put_native_u4(p, x);

   }

   static inline void put_Java_u8(address p, u8 x) {

     put_native_u8(p, x);

   }

   // No byte-order reversal is needed

   static inline u2 swap_u2(u2 x) { return x; }

   static inline u4 swap_u4(u4 x) { return x; }

   static inline u8 swap_u8(u8 x) { return x; }

 #endif // VM_LITTLE_ENDIAN

 };

 #ifdef VM_LITTLE_ENDIAN

 // The following header contains the implementations of swap_u2,

 // swap_u4, and swap_u8

 #ifdef TARGET_OS_ARCH_linux_zero

 # include "bytes_linux_zero.inline.hpp"

 #endif

 #ifdef TARGET_OS_ARCH_bsd_zero

 # include "bytes_bsd_zero.inline.hpp"

 #endif

 #endif // VM_LITTLE_ENDIAN

 #endif // CPU_ZERO_VM_BYTES_ZERO_HPP