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

   1 /* Double-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_ldbl_opt.h>
  21 #include "math.h"
  22 #include "math_private.h"
  23 #include <fenv_libc.h>
  24
  25 #ifdef __STDC__
  26 double
  27 __sqrt (double x)               /* wrapper sqrt */
  28 #else
  29 double
  30 __sqrt (x)                      /* wrapper sqrt */
  31      double x;
  32 #endif
  33 {
  34   double z;
  35 /* Power4 (ISA V2.0) and above implement sqrt in hardware.  */
  36    __asm __volatile (
  37         "       fsqrt   %0,%1\n"
  38                 : "=f" (z)
  39                 : "f" (x));
  40 #ifdef _IEEE_LIBM
  41   return z;
  42 #else
  43   if (__builtin_expect (_LIB_VERSION == _IEEE_, 0))
  44     return z;
  45
  46   if (__builtin_expect (x != x, 0))
  47     return z;
  48
  49   if  (__builtin_expect (x < 0.0, 0))
  50     return __kernel_standard (x, x, 26);        /* sqrt(negative) */
  51   else
  52     return z;
  53 #endif
  54 }
  55
  56 weak_alias (__sqrt, sqrt)
  57 #ifdef NO_LONG_DOUBLE
  58   strong_alias (__sqrt, __sqrtl) weak_alias (__sqrt, sqrtl)
  59 #endif
  60 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
  61 compat_symbol (libm, __sqrt, sqrtl, GLIBC_2_0);
  62 #endif