96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
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/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/atomics.h>
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#define FUTEX_SYSCALL 240
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#define FUTEX_WAIT 0
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#define FUTEX_WAKE 1
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int __futex_wait(volatile void *ftx, int val)
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{
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int ret;
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asm volatile (
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"int $0x80;"
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: "=a" (ret)
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: "0" (FUTEX_SYSCALL),
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"b" (ftx),
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"c" (FUTEX_WAIT),
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"d" (val),
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"S" (0)
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);
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return ret;
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}
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int __futex_wake(volatile void *ftx, int count)
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{
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int ret;
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asm volatile (
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"int $0x80;"
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: "=a" (ret)
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: "0" (FUTEX_SYSCALL),
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"b" (ftx),
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"c" (FUTEX_WAKE),
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"d" (count)
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);
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return ret;
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}
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int __atomic_cmpxchg(int old, int new, volatile int* addr) {
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int xchg;
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asm volatile (
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"lock;"
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"cmpxchg %%ecx, (%%edx);"
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"setne %%al;"
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: "=a" (xchg)
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: "a" (old),
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"c" (new),
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"d" (addr)
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);
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return xchg;
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}
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int __atomic_swap(int new, volatile int* addr) {
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int old;
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asm volatile (
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"lock;"
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"xchg %%ecx, (%%edx);"
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: "=c" (old)
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: "c" (new),
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"d" (addr)
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);
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return old;
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}
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int __atomic_dec(volatile int* addr) {
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int old;
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do {
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old = *addr;
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} while (atomic_cmpxchg(old, old-1, addr));
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return old;
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}
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