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Optimized floor for 64-bit architectures

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Ulrich Drepper 2011-10-15 21:44:45 -04:00
parent b61099b50a
commit d4a285692a
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2011-10-15 Ulrich Drepper <drepper@gmail.com>
* sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: New file.
* sysdeps/ieee754/dbl-64/e_cosh.c: Cleanup.
* sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c: New file.

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sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c Normal file
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/* Round double to integer away from zero.
Copyright (C) 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 2011.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* Based on a version which carries the following copyright: */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "math.h"
#include "math_private.h"
/*
* floor(x)
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floor(x).
*/
static const double huge = 1.0e300;
double
__floor (double x)
{
int64_t i0;
EXTRACT_WORDS64(i0,x);
int32_t j0 = ((i0>>52)&0x7ff)-0x3ff;
if(__builtin_expect(j0<52, 1)) {
if(j0<0) { /* raise inexact if x != 0 */
if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
if(i0>=0) {i0=0;}
else if((i0&0x7fffffffffffffffl)!=0)
{ i0=0xbff0000000000000l;}
}
} else {
uint64_t i = (0x000fffffffffffffl)>>j0;
if((i0&i)==0) return x; /* x is integral */
if(huge+x>0.0) { /* raise inexact flag */
if(i0<0) i0 += (0x0010000000000000l)>>j0;
i0 &= (~i);
}
}
INSERT_WORDS64(x,i0);
} else if (j0==0x400)
return x+x; /* inf or NaN */
return x;
}
weak_alias (__floor, floor)
#ifdef NO_LONG_DOUBLE
strong_alias (__floor, __floorl)
weak_alias (__floor, floorl)
#endif