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. is_Java_byte_ordering_different()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. get_native_u2(address p)51 static inline u2 get_native_u2(address p){ 52 unaligned *up = (unaligned *) p; 53 return up->us; 54 } 55 get_native_u4(address p)56 static inline u4 get_native_u4(address p) { 57 unaligned *up = (unaligned *) p; 58 return up->u; 59 } 60 get_native_u8(address p)61 static inline u8 get_native_u8(address p) { 62 unaligned *up = (unaligned *) p; 63 return up->ul; 64 } 65 put_native_u2(address p,u2 x)66 static inline void put_native_u2(address p, u2 x) { 67 unaligned *up = (unaligned *) p; 68 up->us = x; 69 } 70 put_native_u4(address p,u4 x)71 static inline void put_native_u4(address p, u4 x) { 72 unaligned *up = (unaligned *) p; 73 up->u = x; 74 } 75 put_native_u8(address p,u8 x)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 get_Java_u2(address p)85 static inline u2 get_Java_u2(address p) { 86 return (u2(p[0]) << 8) | 87 (u2(p[1]) ); 88 } get_Java_u4(address p)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 } get_Java_u8(address p)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 put_Java_u2(address p,u2 x)108 static inline void put_Java_u2(address p, u2 x) { 109 p[0] = x >> 8; 110 p[1] = x; 111 } put_Java_u4(address p,u4 x)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 } put_Java_u8(address p,u8 x)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 get_Java_u2(address p)138 static inline u2 get_Java_u2(address p) { 139 return get_native_u2(p); 140 } get_Java_u4(address p)141 static inline u4 get_Java_u4(address p) { 142 return get_native_u4(p); 143 } get_Java_u8(address p)144 static inline u8 get_Java_u8(address p) { 145 return get_native_u8(p); 146 } 147 put_Java_u2(address p,u2 x)148 static inline void put_Java_u2(address p, u2 x) { 149 put_native_u2(p, x); 150 } put_Java_u4(address p,u4 x)151 static inline void put_Java_u4(address p, u4 x) { 152 put_native_u4(p, x); 153 } put_Java_u8(address p,u8 x)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 swap_u2(u2 x)159 static inline u2 swap_u2(u2 x) { return x; } swap_u4(u4 x)160 static inline u4 swap_u4(u4 x) { return x; } swap_u8(u8 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 #ifdef TARGET_OS_ARCH_bsd_zero 172 # include "bytes_bsd_zero.inline.hpp" 173 #endif 174 175 #endif // VM_LITTLE_ENDIAN 176 177 #endif // CPU_ZERO_VM_BYTES_ZERO_HPP 178