f2615995a7
* sysdeps/unix/i386/i686/tempname.c: New file. * sysdeps/posix/tempname.c (__gen_tempname): If RANDOM_BITS is defined use this macro to get some bits of randomness instead of the usual gettimeofday or time calls. 2001-03-16 Paul Eggert <eggert@twinsun.com> * sysdeps/posix/tempname.c (uint64_t): Define to uintmax_t if not defined, and if UINT64_MAX is not defined. 2001-03-19 Ulrich Drepper <drepper@redhat.com>
36 lines
1.6 KiB
C
36 lines
1.6 KiB
C
/* Copyright (C) 2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* For i686 and up we have a better and faster source of random bits in the
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form of the time stamp counter. */
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#define RANDOM_BITS(Var) \
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if (__builtin_expect (value == UINT64_C (0), 0)) \
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{ \
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/* If this is the first time this function is used initialize \
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the variable we accumulate the value in to some somewhat \
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random value. If we'd not do this programs at startup time \
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might have a reduced set of possible names, at least on slow \
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machines. */ \
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struct timeval tv; \
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__gettimeofday (&tv, NULL); \
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value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \
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} \
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__asm__ __volatile__ ("rdtsc" : "=A" (Var))
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#include_next <tempname.c>
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