/*

 * 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