1/* 2 * Copyright (c) 2006, 2016, 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#include "precompiled.hpp" 26#include "runtime/sharedRuntime.hpp" 27#include "utilities/align.hpp" 28#include "utilities/copy.hpp" 29 30 31// Copy bytes; larger units are filled atomically if everything is aligned. 32void Copy::conjoint_memory_atomic(void* from, void* to, size_t size) { 33 address src = (address) from; 34 address dst = (address) to; 35 uintptr_t bits = (uintptr_t) src | (uintptr_t) dst | (uintptr_t) size; 36 37 // (Note: We could improve performance by ignoring the low bits of size, 38 // and putting a short cleanup loop after each bulk copy loop. 39 // There are plenty of other ways to make this faster also, 40 // and it's a slippery slope. For now, let's keep this code simple 41 // since the simplicity helps clarify the atomicity semantics of 42 // this operation. There are also CPU-specific assembly versions 43 // which may or may not want to include such optimizations.) 44 45 if (bits % sizeof(jlong) == 0) { 46 Copy::conjoint_jlongs_atomic((jlong*) src, (jlong*) dst, size / sizeof(jlong)); 47 } else if (bits % sizeof(jint) == 0) { 48 Copy::conjoint_jints_atomic((jint*) src, (jint*) dst, size / sizeof(jint)); 49 } else if (bits % sizeof(jshort) == 0) { 50 Copy::conjoint_jshorts_atomic((jshort*) src, (jshort*) dst, size / sizeof(jshort)); 51 } else { 52 // Not aligned, so no need to be atomic. 53 Copy::conjoint_jbytes((void*) src, (void*) dst, size); 54 } 55} 56 57class CopySwap : AllStatic { 58public: 59 /** 60 * Copy and optionally byte swap elements 61 * 62 * <swap> - true if elements should be byte swapped 63 * 64 * @param src address of source 65 * @param dst address of destination 66 * @param byte_count number of bytes to copy 67 * @param elem_size size of the elements to copy-swap 68 */ 69 template<bool swap> 70 static void conjoint_swap_if_needed(const void* src, void* dst, size_t byte_count, size_t elem_size) { 71 assert(src != NULL, "address must not be NULL"); 72 assert(dst != NULL, "address must not be NULL"); 73 assert(elem_size == 2 || elem_size == 4 || elem_size == 8, 74 "incorrect element size: " SIZE_FORMAT, elem_size); 75 assert(is_aligned(byte_count, elem_size), 76 "byte_count " SIZE_FORMAT " must be multiple of element size " SIZE_FORMAT, byte_count, elem_size); 77 78 address src_end = (address)src + byte_count; 79 80 if (dst <= src || dst >= src_end) { 81 do_conjoint_swap<RIGHT,swap>(src, dst, byte_count, elem_size); 82 } else { 83 do_conjoint_swap<LEFT,swap>(src, dst, byte_count, elem_size); 84 } 85 } 86 87private: 88 /** 89 * Byte swap a 16-bit value 90 */ 91 static uint16_t byte_swap(uint16_t x) { 92 return (x << 8) | (x >> 8); 93 } 94 95 /** 96 * Byte swap a 32-bit value 97 */ 98 static uint32_t byte_swap(uint32_t x) { 99 uint16_t lo = (uint16_t)x; 100 uint16_t hi = (uint16_t)(x >> 16); 101 102 return ((uint32_t)byte_swap(lo) << 16) | (uint32_t)byte_swap(hi); 103 } 104 105 /** 106 * Byte swap a 64-bit value 107 */ 108 static uint64_t byte_swap(uint64_t x) { 109 uint32_t lo = (uint32_t)x; 110 uint32_t hi = (uint32_t)(x >> 32); 111 112 return ((uint64_t)byte_swap(lo) << 32) | (uint64_t)byte_swap(hi); 113 } 114 115 enum CopyDirection { 116 RIGHT, // lower -> higher address 117 LEFT // higher -> lower address 118 }; 119 120 /** 121 * Copy and byte swap elements 122 * 123 * <T> - type of element to copy 124 * <D> - copy direction 125 * <is_src_aligned> - true if src argument is aligned to element size 126 * <is_dst_aligned> - true if dst argument is aligned to element size 127 * 128 * @param src address of source 129 * @param dst address of destination 130 * @param byte_count number of bytes to copy 131 */ 132 template <typename T, CopyDirection D, bool swap, bool is_src_aligned, bool is_dst_aligned> 133 static void do_conjoint_swap(const void* src, void* dst, size_t byte_count) { 134 const char* cur_src; 135 char* cur_dst; 136 137 switch (D) { 138 case RIGHT: 139 cur_src = (const char*)src; 140 cur_dst = (char*)dst; 141 break; 142 case LEFT: 143 cur_src = (const char*)src + byte_count - sizeof(T); 144 cur_dst = (char*)dst + byte_count - sizeof(T); 145 break; 146 } 147 148 for (size_t i = 0; i < byte_count / sizeof(T); i++) { 149 T tmp; 150 151 if (is_src_aligned) { 152 tmp = *(T*)cur_src; 153 } else { 154 memcpy(&tmp, cur_src, sizeof(T)); 155 } 156 157 if (swap) { 158 tmp = byte_swap(tmp); 159 } 160 161 if (is_dst_aligned) { 162 *(T*)cur_dst = tmp; 163 } else { 164 memcpy(cur_dst, &tmp, sizeof(T)); 165 } 166 167 switch (D) { 168 case RIGHT: 169 cur_src += sizeof(T); 170 cur_dst += sizeof(T); 171 break; 172 case LEFT: 173 cur_src -= sizeof(T); 174 cur_dst -= sizeof(T); 175 break; 176 } 177 } 178 } 179 180 /** 181 * Copy and byte swap elements 182 * 183 * <T> - type of element to copy 184 * <D> - copy direction 185 * <swap> - true if elements should be byte swapped 186 * 187 * @param src address of source 188 * @param dst address of destination 189 * @param byte_count number of bytes to copy 190 */ 191 template <typename T, CopyDirection direction, bool swap> 192 static void do_conjoint_swap(const void* src, void* dst, size_t byte_count) { 193 if (is_aligned(src, sizeof(T))) { 194 if (is_aligned(dst, sizeof(T))) { 195 do_conjoint_swap<T,direction,swap,true,true>(src, dst, byte_count); 196 } else { 197 do_conjoint_swap<T,direction,swap,true,false>(src, dst, byte_count); 198 } 199 } else { 200 if (is_aligned(dst, sizeof(T))) { 201 do_conjoint_swap<T,direction,swap,false,true>(src, dst, byte_count); 202 } else { 203 do_conjoint_swap<T,direction,swap,false,false>(src, dst, byte_count); 204 } 205 } 206 } 207 208 209 /** 210 * Copy and byte swap elements 211 * 212 * <D> - copy direction 213 * <swap> - true if elements should be byte swapped 214 * 215 * @param src address of source 216 * @param dst address of destination 217 * @param byte_count number of bytes to copy 218 * @param elem_size size of the elements to copy-swap 219 */ 220 template <CopyDirection D, bool swap> 221 static void do_conjoint_swap(const void* src, void* dst, size_t byte_count, size_t elem_size) { 222 switch (elem_size) { 223 case 2: do_conjoint_swap<uint16_t,D,swap>(src, dst, byte_count); break; 224 case 4: do_conjoint_swap<uint32_t,D,swap>(src, dst, byte_count); break; 225 case 8: do_conjoint_swap<uint64_t,D,swap>(src, dst, byte_count); break; 226 default: guarantee(false, "do_conjoint_swap: Invalid elem_size " SIZE_FORMAT "\n", elem_size); 227 } 228 } 229}; 230 231void Copy::conjoint_copy(const void* src, void* dst, size_t byte_count, size_t elem_size) { 232 CopySwap::conjoint_swap_if_needed<false>(src, dst, byte_count, elem_size); 233} 234 235void Copy::conjoint_swap(const void* src, void* dst, size_t byte_count, size_t elem_size) { 236 CopySwap::conjoint_swap_if_needed<true>(src, dst, byte_count, elem_size); 237} 238 239// Fill bytes; larger units are filled atomically if everything is aligned. 240void Copy::fill_to_memory_atomic(void* to, size_t size, jubyte value) { 241 address dst = (address) to; 242 uintptr_t bits = (uintptr_t) to | (uintptr_t) size; 243 if (bits % sizeof(jlong) == 0) { 244 jlong fill = (julong)( (jubyte)value ); // zero-extend 245 if (fill != 0) { 246 fill += fill << 8; 247 fill += fill << 16; 248 fill += fill << 32; 249 } 250 //Copy::fill_to_jlongs_atomic((jlong*) dst, size / sizeof(jlong)); 251 for (uintptr_t off = 0; off < size; off += sizeof(jlong)) { 252 *(jlong*)(dst + off) = fill; 253 } 254 } else if (bits % sizeof(jint) == 0) { 255 jint fill = (juint)( (jubyte)value ); // zero-extend 256 if (fill != 0) { 257 fill += fill << 8; 258 fill += fill << 16; 259 } 260 //Copy::fill_to_jints_atomic((jint*) dst, size / sizeof(jint)); 261 for (uintptr_t off = 0; off < size; off += sizeof(jint)) { 262 *(jint*)(dst + off) = fill; 263 } 264 } else if (bits % sizeof(jshort) == 0) { 265 jshort fill = (jushort)( (jubyte)value ); // zero-extend 266 fill += fill << 8; 267 //Copy::fill_to_jshorts_atomic((jshort*) dst, size / sizeof(jshort)); 268 for (uintptr_t off = 0; off < size; off += sizeof(jshort)) { 269 *(jshort*)(dst + off) = fill; 270 } 271 } else { 272 // Not aligned, so no need to be atomic. 273 Copy::fill_to_bytes(dst, size, value); 274 } 275} 276