hotspot/src/cpu/x86/vm/bytes_x86.hpp
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     1 /*
       
     2  * Copyright 1997-2001 Sun Microsystems, Inc.  All Rights Reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.
       
     8  *
       
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    12  * version 2 for more details (a copy is included in the LICENSE file that
       
    13  * accompanied this code).
       
    14  *
       
    15  * You should have received a copy of the GNU General Public License version
       
    16  * 2 along with this work; if not, write to the Free Software Foundation,
       
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    18  *
       
    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
       
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
       
    21  * have any questions.
       
    22  *
       
    23  */
       
    24 
       
    25 class Bytes: AllStatic {
       
    26  private:
       
    27 #ifndef AMD64
       
    28   // Helper function for swap_u8
       
    29   static inline u8   swap_u8_base(u4 x, u4 y);        // compiler-dependent implementation
       
    30 #endif // AMD64
       
    31 
       
    32  public:
       
    33   // Returns true if the byte ordering used by Java is different from the native byte ordering
       
    34   // of the underlying machine. For example, this is true for Intel x86, but false for Solaris
       
    35   // on Sparc.
       
    36   static inline bool is_Java_byte_ordering_different(){ return true; }
       
    37 
       
    38 
       
    39   // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering
       
    40   // (no special code is needed since x86 CPUs can access unaligned data)
       
    41   static inline u2   get_native_u2(address p)         { return *(u2*)p; }
       
    42   static inline u4   get_native_u4(address p)         { return *(u4*)p; }
       
    43   static inline u8   get_native_u8(address p)         { return *(u8*)p; }
       
    44 
       
    45   static inline void put_native_u2(address p, u2 x)   { *(u2*)p = x; }
       
    46   static inline void put_native_u4(address p, u4 x)   { *(u4*)p = x; }
       
    47   static inline void put_native_u8(address p, u8 x)   { *(u8*)p = x; }
       
    48 
       
    49 
       
    50   // Efficient reading and writing of unaligned unsigned data in Java
       
    51   // byte ordering (i.e. big-endian ordering). Byte-order reversal is
       
    52   // needed since x86 CPUs use little-endian format.
       
    53   static inline u2   get_Java_u2(address p)           { return swap_u2(get_native_u2(p)); }
       
    54   static inline u4   get_Java_u4(address p)           { return swap_u4(get_native_u4(p)); }
       
    55   static inline u8   get_Java_u8(address p)           { return swap_u8(get_native_u8(p)); }
       
    56 
       
    57   static inline void put_Java_u2(address p, u2 x)     { put_native_u2(p, swap_u2(x)); }
       
    58   static inline void put_Java_u4(address p, u4 x)     { put_native_u4(p, swap_u4(x)); }
       
    59   static inline void put_Java_u8(address p, u8 x)     { put_native_u8(p, swap_u8(x)); }
       
    60 
       
    61 
       
    62   // Efficient swapping of byte ordering
       
    63   static inline u2   swap_u2(u2 x);                   // compiler-dependent implementation
       
    64   static inline u4   swap_u4(u4 x);                   // compiler-dependent implementation
       
    65   static inline u8   swap_u8(u8 x);
       
    66 };
       
    67 
       
    68 
       
    69 // The following header contains the implementations of swap_u2, swap_u4, and swap_u8[_base]
       
    70 #include "incls/_bytes_pd.inline.hpp.incl"