1 /*
   2  * Copyright (c) 2006, 2007, 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 "incls/_precompiled.incl"
  26 # include "incls/_copy.cpp.incl"
  27 
  28 
  29 // Copy bytes; larger units are filled atomically if everything is aligned.
  30 void Copy::conjoint_memory_atomic(void* from, void* to, size_t size) {
  31   address src = (address) from;
  32   address dst = (address) to;
  33   uintptr_t bits = (uintptr_t) src | (uintptr_t) dst | (uintptr_t) size;
  34 
  35   // (Note:  We could improve performance by ignoring the low bits of size,
  36   // and putting a short cleanup loop after each bulk copy loop.
  37   // There are plenty of other ways to make this faster also,
  38   // and it's a slippery slope.  For now, let's keep this code simple
  39   // since the simplicity helps clarify the atomicity semantics of
  40   // this operation.  There are also CPU-specific assembly versions
  41   // which may or may not want to include such optimizations.)
  42 
  43   if (bits % sizeof(jlong) == 0) {
  44     Copy::conjoint_jlongs_atomic((jlong*) src, (jlong*) dst, size / sizeof(jlong));
  45   } else if (bits % sizeof(jint) == 0) {
  46     Copy::conjoint_jints_atomic((jint*) src, (jint*) dst, size / sizeof(jint));
  47   } else if (bits % sizeof(jshort) == 0) {
  48     Copy::conjoint_jshorts_atomic((jshort*) src, (jshort*) dst, size / sizeof(jshort));
  49   } else {
  50     // Not aligned, so no need to be atomic.
  51     Copy::conjoint_bytes((void*) src, (void*) dst, size);
  52   }
  53 }
  54 
  55 
  56 // Fill bytes; larger units are filled atomically if everything is aligned.
  57 void Copy::fill_to_memory_atomic(void* to, size_t size, jubyte value) {
  58   address dst = (address) to;
  59   uintptr_t bits = (uintptr_t) to | (uintptr_t) size;
  60   if (bits % sizeof(jlong) == 0) {
  61     jlong fill = (julong)( (jubyte)value ); // zero-extend
  62     if (fill != 0) {
  63       fill += fill << 8;
  64       fill += fill << 16;
  65       fill += fill << 32;
  66     }
  67     //Copy::fill_to_jlongs_atomic((jlong*) dst, size / sizeof(jlong));
  68     for (uintptr_t off = 0; off < size; off += sizeof(jlong)) {
  69       *(jlong*)(dst + off) = fill;
  70     }
  71   } else if (bits % sizeof(jint) == 0) {
  72     jint fill = (juint)( (jubyte)value ); // zero-extend
  73     if (fill != 0) {
  74       fill += fill << 8;
  75       fill += fill << 16;
  76     }
  77     //Copy::fill_to_jints_atomic((jint*) dst, size / sizeof(jint));
  78     for (uintptr_t off = 0; off < size; off += sizeof(jint)) {
  79       *(jint*)(dst + off) = fill;
  80     }
  81   } else if (bits % sizeof(jshort) == 0) {
  82     jshort fill = (jushort)( (jubyte)value ); // zero-extend
  83     fill += fill << 8;
  84     //Copy::fill_to_jshorts_atomic((jshort*) dst, size / sizeof(jshort));
  85     for (uintptr_t off = 0; off < size; off += sizeof(jshort)) {
  86       *(jshort*)(dst + off) = fill;
  87     }
  88   } else {
  89     // Not aligned, so no need to be atomic.
  90     Copy::fill_to_bytes(dst, size, value);
  91   }
  92 }