1 /*
2 * Copyright (c) 1997, 2010, 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 #ifndef CPU_ZERO_VM_BYTES_ZERO_HPP
27 #define CPU_ZERO_VM_BYTES_ZERO_HPP
28
29 #include "memory/allocation.hpp"
30
31 typedef union unaligned {
32 u4 u;
33 u2 us;
34 u8 ul;
35 } __attribute__((packed)) unaligned;
36
37 class Bytes: AllStatic {
38 public:
39 // Returns true if the byte ordering used by Java is different
40 // from the native byte ordering of the underlying machine.
41 static inline bool is_Java_byte_ordering_different() {
42 #ifdef VM_LITTLE_ENDIAN
43 return true;
44 #else
45 return false;
46 #endif
47 }
48
49 // Efficient reading and writing of unaligned unsigned data in
50 // platform-specific byte ordering.
51 static inline u2 get_native_u2(address p){
52 unaligned *up = (unaligned *) p;
53 return up->us;
54 }
55
56 static inline u4 get_native_u4(address p) {
57 unaligned *up = (unaligned *) p;
58 return up->u;
59 }
60
61 static inline u8 get_native_u8(address p) {
62 unaligned *up = (unaligned *) p;
63 return up->ul;
64 }
65
66 static inline void put_native_u2(address p, u2 x) {
67 unaligned *up = (unaligned *) p;
68 up->us = x;
69 }
70
71 static inline void put_native_u4(address p, u4 x) {
72 unaligned *up = (unaligned *) p;
73 up->u = x;
74 }
75
76 static inline void put_native_u8(address p, u8 x) {
77 unaligned *up = (unaligned *) p;
78 up->ul = x;
79 }
80
81 // Efficient reading and writing of unaligned unsigned data in Java
82 // byte ordering (i.e. big-endian ordering).
83 #ifdef VM_LITTLE_ENDIAN
84 // Byte-order reversal is needed
85 static inline u2 get_Java_u2(address p) {
86 return (u2(p[0]) << 8) |
87 (u2(p[1]) );
88 }
89 static inline u4 get_Java_u4(address p) {
90 return (u4(p[0]) << 24) |
91 (u4(p[1]) << 16) |
92 (u4(p[2]) << 8) |
93 (u4(p[3]) );
94 }
95 static inline u8 get_Java_u8(address p) {
96 u4 hi, lo;
97 hi = (u4(p[0]) << 24) |
98 (u4(p[1]) << 16) |
99 (u4(p[2]) << 8) |
100 (u4(p[3]) );
101 lo = (u4(p[4]) << 24) |
102 (u4(p[5]) << 16) |
103 (u4(p[6]) << 8) |
104 (u4(p[7]) );
105 return u8(lo) | (u8(hi) << 32);
106 }
107
108 static inline void put_Java_u2(address p, u2 x) {
109 p[0] = x >> 8;
110 p[1] = x;
111 }
112 static inline void put_Java_u4(address p, u4 x) {
113 p[0] = x >> 24;
114 p[1] = x >> 16;
115 p[2] = x >> 8;
116 p[3] = x;
117 }
118 static inline void put_Java_u8(address p, u8 x) {
119 u4 hi, lo;
120 lo = x;
121 hi = x >> 32;
122 p[0] = hi >> 24;
123 p[1] = hi >> 16;
124 p[2] = hi >> 8;
125 p[3] = hi;
126 p[4] = lo >> 24;
127 p[5] = lo >> 16;
128 p[6] = lo >> 8;
129 p[7] = lo;
130 }
131
132 // Efficient swapping of byte ordering
133 static inline u2 swap_u2(u2 x);
134 static inline u4 swap_u4(u4 x);
135 static inline u8 swap_u8(u8 x);
136 #else
137 // No byte-order reversal is needed
138 static inline u2 get_Java_u2(address p) {
139 return get_native_u2(p);
140 }
141 static inline u4 get_Java_u4(address p) {
142 return get_native_u4(p);
143 }
144 static inline u8 get_Java_u8(address p) {
145 return get_native_u8(p);
146 }
147
148 static inline void put_Java_u2(address p, u2 x) {
149 put_native_u2(p, x);
150 }
151 static inline void put_Java_u4(address p, u4 x) {
152 put_native_u4(p, x);
153 }
154 static inline void put_Java_u8(address p, u8 x) {
155 put_native_u8(p, x);
156 }
157
158 // No byte-order reversal is needed
159 static inline u2 swap_u2(u2 x) { return x; }
160 static inline u4 swap_u4(u4 x) { return x; }
161 static inline u8 swap_u8(u8 x) { return x; }
162 #endif // VM_LITTLE_ENDIAN
163 };
164
165 #ifdef VM_LITTLE_ENDIAN
166 // The following header contains the implementations of swap_u2,
167 // swap_u4, and swap_u8
168 #ifdef TARGET_OS_ARCH_linux_zero
169 # include "bytes_linux_zero.inline.hpp"
170 #endif
171
172 #endif // VM_LITTLE_ENDIAN
173
174 #endif // CPU_ZERO_VM_BYTES_ZERO_HPP