bytes_x86.hpp revision 1472:c18cbe5936b8 
1/*
2 * Copyright (c) 1997, 2001, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25class 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"
71