sysdeps/alpha/fpu/s_floor.c

   1 /* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Richard Henderson.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <math.h>
  21
  22
  23 /* Use the -inf rounding mode conversion instructions to implement
  24    floor.  We note when the exponent is large enough that the value
  25    must be integral, as this avoids unpleasant integer overflows.  */
  26
  27 double
  28 __floor (double x)
  29 {
  30   /* Check not zero since floor(-0) == -0.  */
  31   if (x != 0 && fabs (x) < 9007199254740992.0)  /* 1 << DBL_MANT_DIG */
  32     {
  33       double __tmp1;
  34       __asm (
  35 #ifdef _IEEE_FP_INEXACT
  36              "cvttq/svim %2,%1\n\t"
  37 #else
  38              "cvttq/svm %2,%1\n\t"
  39 #endif
  40              "cvtqt/m %1,%0\n\t"
  41              : "=f"(x), "=&f"(__tmp1)
  42              : "f"(x));
  43     }
  44   return x;
  45 }
  46
  47 weak_alias (__floor, floor)
  48 #ifdef NO_LONG_DOUBLE
  49 strong_alias (__floor, __floorl)
  50 weak_alias (__floor, floorl)
  51 #endif