jdk8-mips64-public/hotspot: src/share/vm/runtime/atomic.cpp@0715f0cf171d

     1 /*

     2  * Copyright (c) 2001, 2008, 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  */

    25 # include "incls/_precompiled.incl"

    26 # include "incls/_atomic.cpp.incl"

    28 jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {

    29   assert(sizeof(jbyte) == 1, "assumption.");

    30   uintptr_t dest_addr = (uintptr_t)dest;

    31   uintptr_t offset = dest_addr % sizeof(jint);

    32   volatile jint* dest_int = (volatile jint*)(dest_addr - offset);

    33   jint cur = *dest_int;

    34   jbyte* cur_as_bytes = (jbyte*)(&cur);

    35   jint new_val = cur;

    36   jbyte* new_val_as_bytes = (jbyte*)(&new_val);

    37   new_val_as_bytes[offset] = exchange_value;

    38   while (cur_as_bytes[offset] == compare_value) {

    39     jint res = cmpxchg(new_val, dest_int, cur);

    40     if (res == cur) break;

    41     cur = res;

    42     new_val = cur;

    43     new_val_as_bytes[offset] = exchange_value;

    44   }

    45   return cur_as_bytes[offset];

    46 }

    48 unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {

    49   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");

    50   return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);

    51 }

    53 unsigned Atomic::cmpxchg(unsigned int exchange_value,

    54                          volatile unsigned int* dest, unsigned int compare_value) {

    55   assert(sizeof(unsigned int) == sizeof(jint), "more work to do");

    56   return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest,

    57                                        (jint)compare_value);

    58 }

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