1 /* 2 * Copyright (c) 1997, 2010, 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_VM_BYTES_X86_HPP 26 #define CPU_X86_VM_BYTES_X86_HPP 27 28 #include "memory/allocation.hpp" 29 30 class Bytes: AllStatic { 31 private: 32 #ifndef AMD64 33 // Helper function for swap_u8 34 static inline u8 swap_u8_base(u4 x, u4 y); // compiler-dependent implementation 35 #endif // AMD64 36 37 public: 38 // Returns true if the byte ordering used by Java is different from the native byte ordering 39 // of the underlying machine. For example, this is true for Intel x86, but false for Solaris 40 // on Sparc. 41 static inline bool is_Java_byte_ordering_different(){ return true; } 42 43 44 // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering 45 // (no special code is needed since x86 CPUs can access unaligned data) 46 static inline u2 get_native_u2(address p) { return *(u2*)p; } 47 static inline u4 get_native_u4(address p) { return *(u4*)p; } 48 static inline u8 get_native_u8(address p) { return *(u8*)p; } 49 50 static inline void put_native_u2(address p, u2 x) { *(u2*)p = x; } 51 static inline void put_native_u4(address p, u4 x) { *(u4*)p = x; } 52 static inline void put_native_u8(address p, u8 x) { *(u8*)p = x; } 53 54 55 // Efficient reading and writing of unaligned unsigned data in Java 56 // byte ordering (i.e. big-endian ordering). Byte-order reversal is 57 // needed since x86 CPUs use little-endian format. 58 static inline u2 get_Java_u2(address p) { return swap_u2(get_native_u2(p)); } 59 static inline u4 get_Java_u4(address p) { return swap_u4(get_native_u4(p)); } 60 static inline u8 get_Java_u8(address p) { return swap_u8(get_native_u8(p)); } 61 62 static inline void put_Java_u2(address p, u2 x) { put_native_u2(p, swap_u2(x)); } 63 static inline void put_Java_u4(address p, u4 x) { put_native_u4(p, swap_u4(x)); } 64 static inline void put_Java_u8(address p, u8 x) { put_native_u8(p, swap_u8(x)); } 65 66 67 // Efficient swapping of byte ordering 68 static inline u2 swap_u2(u2 x); // compiler-dependent implementation 69 static inline u4 swap_u4(u4 x); // compiler-dependent implementation 70 static inline u8 swap_u8(u8 x); 71 }; 72 73 74 // The following header contains the implementations of swap_u2, swap_u4, and swap_u8[_base] 75 #ifdef TARGET_OS_ARCH_linux_x86 76 # include "bytes_linux_x86.inline.hpp" 77 #endif 78 #ifdef TARGET_OS_ARCH_solaris_x86 79 # include "bytes_solaris_x86.inline.hpp" 80 #endif 81 #ifdef TARGET_OS_ARCH_windows_x86 82 # include "bytes_windows_x86.inline.hpp" 83 #endif 84 85 86 #endif // CPU_X86_VM_BYTES_X86_HPP