sysdeps/alpha/fpu/s_round.c

   1 /* Copyright (C) 2007 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <math.h>
  20 #include <math_ldbl_opt.h>
  21
  22
  23 double
  24 __round (double x)
  25 {
  26   const double almost_half = 0x1.fffffffffffffp-2;
  27   const double two52 = 0x1.0p52;
  28   double tmp, r;
  29
  30   __asm (
  31 #ifdef _IEEE_FP_INEXACT
  32          "addt/suic %2, %3, %1\n\tsubt/suic %1, %3, %0"
  33 #else
  34          "addt/suc %2, %3, %1\n\tsubt/suc %1, %3, %0"
  35 #endif
  36          : "=&f"(r), "=&f"(tmp)
  37          : "f"(fabs (x) + almost_half), "f"(two52));
  38
  39   return copysign (r, x);
  40 }
  41
  42 weak_alias (__round, round)
  43 #ifdef NO_LONG_DOUBLE
  44 strong_alias (__round, __roundl)
  45 weak_alias (__roundl, roundl)
  46 #endif
  47 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
  48 compat_symbol (libm, __round, roundl, GLIBC_2_1);
  49 #endif