sysdeps/powerpc/powerpc64/power4/fpu/w_sqrtf.c

   1 /* Single-precision floating point square root wrapper.
   2    Copyright (C) 2004, 2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include "math.h"
  21 #include "math_private.h"
  22 #include <fenv_libc.h>
  23
  24 #include <sysdep.h>
  25 #include <ldsodefs.h>
  26
  27 #ifdef __STDC__
  28 float
  29 __sqrtf (float x)               /* wrapper sqrtf */
  30 #else
  31 float
  32 __sqrtf (x)                     /* wrapper sqrtf */
  33      float x;
  34 #endif
  35 {
  36 #ifdef _IEEE_LIBM
  37   return __ieee754_sqrtf (x);
  38 #else
  39   float z;
  40 /* Power4 (ISA V2.0) and above implement sqrtf in hardware.  */
  41    __asm __volatile (
  42         "       fsqrts  %0,%1\n"
  43                 : "=f" (z)
  44                 : "f" (x));
  45
  46   if (__builtin_expect (_LIB_VERSION == _IEEE_, 0))
  47     return z;
  48
  49   if (__builtin_expect (x != x, 0))
  50     return z;
  51
  52   if  (__builtin_expect (x < 0.0, 0))
  53     /* sqrtf(negative) */
  54     return (float) __kernel_standard ((double) x, (double) x, 126);
  55   else
  56     return z;
  57 #endif
  58 }
  59
  60 weak_alias (__sqrtf, sqrtf)