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b1d9d11be1
This change simplifies the thread-local storage support code. On Windows and Mac OS X the startup latency of __enable_tls() has been reduced from 30ms to 1ms. On Windows, TLS memory accesses will now go much faster due to better self-modifying code that prevents a function call and acquires our thread information block pointer in a single instruction.
32 lines
2.1 KiB
C
32 lines
2.1 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 2022 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/errno.h"
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#include "libc/nexgen32e/gettls.h"
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#include "libc/nexgen32e/threaded.h"
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/**
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* Returns address of errno variable.
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*
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* @see __initialize_tls()
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* @see __install_tls()
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*/
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privileged nocallersavedregisters errno_t *(__errno_location)(void) {
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if (!__tls_enabled) return &__errno;
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return (errno_t *)(__get_tls_privileged() + 0x3c);
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}
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