1 /* 2 * Copyright (c) 1997, 2019, 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. 22 * 23 */ 24 25 #ifndef CPU_X86_BYTES_X86_HPP 26 #define CPU_X86_BYTES_X86_HPP 27 28 #include "memory/allocation.hpp" 29 #include "utilities/align.hpp" 30 #include "utilities/macros.hpp" 31 32 class Bytes: AllStatic { 33 private: 34 #ifndef AMD64 35 // Helper function for swap_u8 36 static inline u8 swap_u8_base(u4 x, u4 y); // compiler-dependent implementation 37 #endif // AMD64 38 39 public: 40 // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering 41 template <typename T> get_native(const void * p)42 static inline T get_native(const void* p) { 43 assert(p != NULL, "null pointer"); 44 45 T x; 46 47 if (is_aligned(p, sizeof(T))) { 48 x = *(T*)p; 49 } else { 50 memcpy(&x, p, sizeof(T)); 51 } 52 53 return x; 54 } 55 56 template <typename T> put_native(void * p,T x)57 static inline void put_native(void* p, T x) { 58 assert(p != NULL, "null pointer"); 59 60 if (is_aligned(p, sizeof(T))) { 61 *(T*)p = x; 62 } else { 63 memcpy(p, &x, sizeof(T)); 64 } 65 } 66 get_native_u2(address p)67 static inline u2 get_native_u2(address p) { return get_native<u2>((void*)p); } get_native_u4(address p)68 static inline u4 get_native_u4(address p) { return get_native<u4>((void*)p); } get_native_u8(address p)69 static inline u8 get_native_u8(address p) { return get_native<u8>((void*)p); } put_native_u2(address p,u2 x)70 static inline void put_native_u2(address p, u2 x) { put_native<u2>((void*)p, x); } put_native_u4(address p,u4 x)71 static inline void put_native_u4(address p, u4 x) { put_native<u4>((void*)p, x); } put_native_u8(address p,u8 x)72 static inline void put_native_u8(address p, u8 x) { put_native<u8>((void*)p, x); } 73 74 // Efficient reading and writing of unaligned unsigned data in Java 75 // byte ordering (i.e. big-endian ordering). Byte-order reversal is 76 // needed since x86 CPUs use little-endian format. 77 template <typename T> get_Java(const address p)78 static inline T get_Java(const address p) { 79 T x = get_native<T>(p); 80 81 if (Endian::is_Java_byte_ordering_different()) { 82 x = swap<T>(x); 83 } 84 85 return x; 86 } 87 88 template <typename T> put_Java(address p,T x)89 static inline void put_Java(address p, T x) { 90 if (Endian::is_Java_byte_ordering_different()) { 91 x = swap<T>(x); 92 } 93 94 put_native<T>(p, x); 95 } 96 get_Java_u2(address p)97 static inline u2 get_Java_u2(address p) { return get_Java<u2>(p); } get_Java_u4(address p)98 static inline u4 get_Java_u4(address p) { return get_Java<u4>(p); } get_Java_u8(address p)99 static inline u8 get_Java_u8(address p) { return get_Java<u8>(p); } 100 put_Java_u2(address p,u2 x)101 static inline void put_Java_u2(address p, u2 x) { put_Java<u2>(p, x); } put_Java_u4(address p,u4 x)102 static inline void put_Java_u4(address p, u4 x) { put_Java<u4>(p, x); } put_Java_u8(address p,u8 x)103 static inline void put_Java_u8(address p, u8 x) { put_Java<u8>(p, x); } 104 105 // Efficient swapping of byte ordering 106 template <typename T> swap(T x)107 static T swap(T x) { 108 switch (sizeof(T)) { 109 case sizeof(u1): return x; 110 case sizeof(u2): return swap_u2(x); 111 case sizeof(u4): return swap_u4(x); 112 case sizeof(u8): return swap_u8(x); 113 default: 114 guarantee(false, "invalid size: " SIZE_FORMAT "\n", sizeof(T)); 115 return 0; 116 } 117 } 118 119 static inline u2 swap_u2(u2 x); // compiler-dependent implementation 120 static inline u4 swap_u4(u4 x); // compiler-dependent implementation 121 static inline u8 swap_u8(u8 x); 122 }; 123 124 // The following header contains the implementations of swap_u2, swap_u4, and swap_u8[_base] 125 #include OS_CPU_HEADER_INLINE(bytes) 126 127 #endif // CPU_X86_BYTES_X86_HPP 128