1 /* 2 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2016 SAP SE. All rights reserved. 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_S390_VM_BYTES_S390_HPP 27 #define CPU_S390_VM_BYTES_S390_HPP 28 29 #include "memory/allocation.hpp" 30 31 class Bytes: AllStatic { 32 public: 33 // Efficient reading and writing of unaligned unsigned data in 34 // platform-specific byte ordering. 35 36 // Use regular load and store for unaligned access. 37 // 38 // On z/Architecture, unaligned loads and stores are supported when using the 39 // "traditional" load (LH, L/LY, LG) and store (STH, ST/STY, STG) instructions. 40 // The penalty for unaligned access is just very few (two or three) ticks, 41 // plus another few (two or three) ticks if the access crosses a cache line boundary. 42 // 43 // In short, it makes no sense on z/Architecture to piecemeal get or put unaligned data. 44 45 // Returns true if the byte ordering used by Java is different from 46 // the native byte ordering of the underlying machine. 47 // z/Arch is big endian, thus, a swap between native and Java ordering 48 // is always a no-op. 49 static inline bool is_Java_byte_ordering_different() { return false; } 50 51 // Only swap on little endian machines => suffix `_le'. 52 static inline u2 swap_u2_le(u2 x) { return x; } 53 static inline u4 swap_u4_le(u4 x) { return x; } 54 static inline u8 swap_u8_le(u8 x) { return x; } 55 56 static inline u2 get_native_u2(address p) { return *(u2*)p; } 57 static inline u4 get_native_u4(address p) { return *(u4*)p; } 58 static inline u8 get_native_u8(address p) { return *(u8*)p; } 59 60 static inline void put_native_u2(address p, u2 x) { *(u2*)p = x; } 61 static inline void put_native_u4(address p, u4 x) { *(u4*)p = x; } 62 static inline void put_native_u8(address p, u8 x) { *(u8*)p = x; } 63 64 #include "bytes_linux_s390.inline.hpp" 65 66 // Efficient reading and writing of unaligned unsigned data in Java byte ordering (i.e. big-endian ordering) 67 static inline u2 get_Java_u2(address p) { return get_native_u2(p); } 68 static inline u4 get_Java_u4(address p) { return get_native_u4(p); } 69 static inline u8 get_Java_u8(address p) { return get_native_u8(p); } 70 71 static inline void put_Java_u2(address p, u2 x) { put_native_u2(p, x); } 72 static inline void put_Java_u4(address p, u4 x) { put_native_u4(p, x); } 73 static inline void put_Java_u8(address p, u8 x) { put_native_u8(p, x); } 74 }; 75 76 #endif // CPU_S390_VM_BYTES_S390_HPP