jdk8-mips64-public/hotspot: src/share/vm/runtime/atomic.cpp@b5cb079ecaa4

     1 /*

     2  * Copyright (c) 2001, 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  */

    25 #include "precompiled.hpp"

    26 #include "runtime/atomic.hpp"

    27 #ifdef TARGET_OS_FAMILY_linux

    28 # include "os_linux.inline.hpp"

    29 #endif

    30 #ifdef TARGET_OS_FAMILY_solaris

    31 # include "os_solaris.inline.hpp"

    32 #endif

    33 #ifdef TARGET_OS_FAMILY_windows

    34 # include "os_windows.inline.hpp"

    35 #endif

    36 #ifdef TARGET_OS_FAMILY_bsd

    37 # include "os_bsd.inline.hpp"

    38 #endif

    40 #include "runtime/atomic.inline.hpp"

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

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

    44   uintptr_t dest_addr = (uintptr_t)dest;

    45   uintptr_t offset = dest_addr % sizeof(jint);

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

    47   jint cur = *dest_int;

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

    49   jint new_val = cur;

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

    51   new_val_as_bytes[offset] = exchange_value;

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

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

    54     if (res == cur) break;

    55     cur = res;

    56     new_val = cur;

    57     new_val_as_bytes[offset] = exchange_value;

    58   }

    59   return cur_as_bytes[offset];

    60 }

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

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

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

    65 }

    67 unsigned Atomic::cmpxchg(unsigned int exchange_value,

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

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

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

    71                                        (jint)compare_value);

    72 }

    74 jlong Atomic::add(jlong    add_value, volatile jlong*    dest) {

    75   jlong old = load(dest);

    76   jlong new_value = old + add_value;

    77   while (old != cmpxchg(new_value, dest, old)) {

    78     old = load(dest);

    79     new_value = old + add_value;

    80   }

    81   return old;

    82 }

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