diff options
Diffstat (limited to 'sysdeps/unix/i386/i686')
| -rw-r--r-- | sysdeps/unix/i386/i686/tempname.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/sysdeps/unix/i386/i686/tempname.c b/sysdeps/unix/i386/i686/tempname.c new file mode 100644 index 0000000000..3d2476e612 --- /dev/null +++ b/sysdeps/unix/i386/i686/tempname.c @@ -0,0 +1,35 @@ +/* Copyright (C) 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* For i686 and up we have a better and faster source of random bits in the + form of the time stamp counter. */ +#define RANDOM_BITS(Var) \ + if (__builtin_expect (value == UINT64_C (0), 0)) \ + { \ + /* If this is the first time this function is used initialize \ + the variable we accumulate the value in to some somewhat \ + random value. If we'd not do this programs at startup time \ + might have a reduced set of possible names, at least on slow \ + machines. */ \ + struct timeval tv; \ + __gettimeofday (&tv, NULL); \ + value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \ + } \ + __asm__ __volatile__ ("rdtsc" : "=A" (Var)) + +#include_next <tempname.c> |