1 /*
2 * Copyright (c) 1997, 2002, Oracle and/or its affiliates. All rights reserved.
3 * Copyright 2007, 2008, 2009 Red Hat, Inc.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 typedef union unaligned {
27 u4 u;
28 u2 us;
29 u8 ul;
30 } __attribute__((packed)) unaligned;
31
32 class Bytes: AllStatic {
33 public:
34 // Returns true if the byte ordering used by Java is different
35 // from the native byte ordering of the underlying machine.
36 static inline bool is_Java_byte_ordering_different() {
37 #ifdef VM_LITTLE_ENDIAN
38 return true;
39 #else
40 return false;
41 #endif
42 }
43
44 // Efficient reading and writing of unaligned unsigned data in
45 // platform-specific byte ordering.
46 static inline u2 get_native_u2(address p){
47 unaligned *up = (unaligned *) p;
48 return up->us;
49 }
50
51 static inline u4 get_native_u4(address p) {
52 unaligned *up = (unaligned *) p;
53 return up->u;
54 }
55
56 static inline u8 get_native_u8(address p) {
57 unaligned *up = (unaligned *) p;
58 return up->ul;
59 }
60
61 static inline void put_native_u2(address p, u2 x) {
62 unaligned *up = (unaligned *) p;
63 up->us = x;
64 }
65
66 static inline void put_native_u4(address p, u4 x) {
67 unaligned *up = (unaligned *) p;
68 up->u = x;
69 }
70
71 static inline void put_native_u8(address p, u8 x) {
72 unaligned *up = (unaligned *) p;
73 up->ul = x;
74 }
75
76 // Efficient reading and writing of unaligned unsigned data in Java
77 // byte ordering (i.e. big-endian ordering).
78 #ifdef VM_LITTLE_ENDIAN
79 // Byte-order reversal is needed
80 static inline u2 get_Java_u2(address p) {
81 return (u2(p[0]) << 8) |
82 (u2(p[1]) );
83 }
84 static inline u4 get_Java_u4(address p) {
85 return (u4(p[0]) << 24) |
86 (u4(p[1]) << 16) |
87 (u4(p[2]) << 8) |
88 (u4(p[3]) );
89 }
90 static inline u8 get_Java_u8(address p) {
91 u4 hi, lo;
92 hi = (u4(p[0]) << 24) |
93 (u4(p[1]) << 16) |
94 (u4(p[2]) << 8) |
95 (u4(p[3]) );
96 lo = (u4(p[4]) << 24) |
97 (u4(p[5]) << 16) |
98 (u4(p[6]) << 8) |
99 (u4(p[7]) );
100 return u8(lo) | (u8(hi) << 32);
101 }
102
103 static inline void put_Java_u2(address p, u2 x) {
104 p[0] = x >> 8;
105 p[1] = x;
106 }
107 static inline void put_Java_u4(address p, u4 x) {
108 p[0] = x >> 24;
109 p[1] = x >> 16;
110 p[2] = x >> 8;
111 p[3] = x;
112 }
113 static inline void put_Java_u8(address p, u8 x) {
114 u4 hi, lo;
115 lo = x;
116 hi = x >> 32;
117 p[0] = hi >> 24;
118 p[1] = hi >> 16;
119 p[2] = hi >> 8;
120 p[3] = hi;
121 p[4] = lo >> 24;
122 p[5] = lo >> 16;
123 p[6] = lo >> 8;
124 p[7] = lo;
125 }
126
127 // Efficient swapping of byte ordering
128 static inline u2 swap_u2(u2 x);
129 static inline u4 swap_u4(u4 x);
130 static inline u8 swap_u8(u8 x);
131 #else
132 // No byte-order reversal is needed
133 static inline u2 get_Java_u2(address p) {
134 return get_native_u2(p);
135 }
136 static inline u4 get_Java_u4(address p) {
137 return get_native_u4(p);
138 }
139 static inline u8 get_Java_u8(address p) {
140 return get_native_u8(p);
141 }
142
143 static inline void put_Java_u2(address p, u2 x) {
144 put_native_u2(p, x);
145 }
146 static inline void put_Java_u4(address p, u4 x) {
147 put_native_u4(p, x);
148 }
149 static inline void put_Java_u8(address p, u8 x) {
150 put_native_u8(p, x);
151 }
152
153 // No byte-order reversal is needed
154 static inline u2 swap_u2(u2 x) { return x; }
155 static inline u4 swap_u4(u4 x) { return x; }
156 static inline u8 swap_u8(u8 x) { return x; }
157 #endif // VM_LITTLE_ENDIAN
158 };
159
160 #ifdef VM_LITTLE_ENDIAN
161 // The following header contains the implementations of swap_u2,
162 // swap_u4, and swap_u8
163 #include "incls/_bytes_pd.inline.hpp.incl"
164 #endif // VM_LITTLE_ENDIAN