mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
046c7ebd4a
- Introduce fast spinlock API - Double rand64() perf w/ spinlock - Improve raise() on New Technology - Support gettid() across platforms - Implement SA_NODEFER on New Technology - Move the lock intrinsics into LIBC_INTRIN - Make SIGTRAP recoverable on New Technology - Block SIGCHLD in wait4() on New Technology - Add threading prototypes for XNU and FreeBSD - Rewrite abort() fixing its minor bugs on XNU/NT - Shave down a lot of the content in libc/bits/bits.h - Let signal handlers modify CPU registers on New Technology
47 lines
2.7 KiB
C
47 lines
2.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/cmpxchg.h"
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/**
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* Compares and exchanges.
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*
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* @param ifthing is uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @param size is automatically supplied by macro wrapper
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* @return true if value was exchanged, otherwise false
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* @see _lockcmpxchg()
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*/
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bool(_cmpxchg)(void *ifthing, intptr_t isequaltome, intptr_t replaceitwithme,
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size_t size) {
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switch (size) {
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case 1:
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return _cmpxchg((int8_t *)ifthing, (int8_t)isequaltome,
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(int8_t)replaceitwithme);
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case 2:
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return _cmpxchg((int16_t *)ifthing, (int16_t)isequaltome,
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(int16_t)replaceitwithme);
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case 4:
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return _cmpxchg((int32_t *)ifthing, (int32_t)isequaltome,
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(int32_t)replaceitwithme);
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case 8:
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return _cmpxchg((int64_t *)ifthing, (int64_t)isequaltome,
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(int64_t)replaceitwithme);
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default:
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return false;
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}
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}
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