mirror of
https://github.com/jart/cosmopolitan.git
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57 lines
2.7 KiB
C
57 lines
2.7 KiB
C
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/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2016 Google Inc. │
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│ │
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│ Licensed under the Apache License, Version 2.0 (the "License"); │
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│ you may not use this file except in compliance with the License. │
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│ You may obtain a copy of the License at │
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│ │
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│ http://www.apache.org/licenses/LICENSE-2.0 │
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│ │
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│ Unless required by applicable law or agreed to in writing, software │
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│ distributed under the License is distributed on an "AS IS" BASIS, │
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│ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. │
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│ See the License for the specific language governing permissions and │
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│ limitations under the License. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "third_party/nsync/atomic.h"
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#include "third_party/nsync/atomic.internal.h"
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#include "third_party/nsync/common.internal.h"
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#include "libc/thread/thread.h"
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asm(".ident\t\"\\n\\n\
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*NSYNC (Apache 2.0)\\n\
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Copyright 2016 Google, Inc.\\n\
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https://github.com/google/nsync\"");
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// clang-format off
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static pthread_key_t waiter_key;
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static nsync_atomic_uint32_ pt_once;
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static void do_once (nsync_atomic_uint32_ *ponce, void (*dest) (void *)) {
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uint32_t o = ATM_LOAD_ACQ (ponce);
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if (o != 2) {
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while (o == 0 && !ATM_CAS_ACQ (ponce, 0, 1)) {
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o = ATM_LOAD (ponce);
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}
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if (o == 0) {
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pthread_key_create (&waiter_key, dest);
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ATM_STORE_REL (ponce, 2);
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}
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while (ATM_LOAD_ACQ (ponce) != 2) {
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nsync_yield_ ();
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}
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}
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}
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void *nsync_per_thread_waiter_ (void (*dest) (void *)) {
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do_once (&pt_once, dest);
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return (pthread_getspecific (waiter_key));
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}
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void nsync_set_per_thread_waiter_ (void *v, void (*dest) (void *)) {
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do_once (&pt_once, dest);
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pthread_setspecific (waiter_key, v);
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}
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