text: /*
   * 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
  