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

   1 /* Double-precision floating point square root wrapper.
   2    Copyright (C) 2004, 2007, 2012 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math_ldbl_opt.h>
  20 #include "math.h"
  21 #include "math_private.h"
  22 #include <fenv_libc.h>
  23
  24 double
  25 __sqrt (double x)               /* wrapper sqrt */
  26 {
  27   double z;
  28 /* Power4 (ISA V2.0) and above implement sqrt in hardware.  */
  29    __asm __volatile (
  30         "       fsqrt   %0,%1\n"
  31                 : "=f" (z)
  32                 : "f" (x));
  33 #ifdef _IEEE_LIBM
  34   return z;
  35 #else
  36   if (__builtin_expect (_LIB_VERSION == _IEEE_, 0))
  37     return z;
  38
  39   if (__builtin_expect (x != x, 0))
  40     return z;
  41
  42   if  (__builtin_expect (x < 0.0, 0))
  43     return __kernel_standard (x, x, 26);        /* sqrt(negative) */
  44   else
  45     return z;
  46 #endif
  47 }
  48
  49 weak_alias (__sqrt, sqrt)
  50 #ifdef NO_LONG_DOUBLE
  51   strong_alias (__sqrt, __sqrtl) weak_alias (__sqrt, sqrtl)
  52 #endif
  53 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
  54 compat_symbol (libm, __sqrt, sqrtl, GLIBC_2_0);
  55 #endif