sysdeps/powerpc/powerpc32/fpu/s_llrintf.c

   1 /* Round a float value to a long long in the current rounding mode.
   2    Copyright (C) 1997-2019 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.h>
  20 #include <math_private.h>
  21 #include <stdint.h>
  22 #include <libm-alias-float.h>
  23
  24 long long int
  25 __llrintf (float x)
  26 {
  27 #ifdef _ARCH_PWR4
  28   /* Assume powerpc64 instructions availability.  */
  29   long long int ret;
  30   __asm__ ("fctid %0, %1" : "=d" (ret) : "d" (x));
  31   return ret;
  32 #else
  33   float rx = rintf (x);
  34   if (HAVE_PPC_FCTIDZ || rx != x)
  35     return (long long int) rx;
  36   else
  37     {
  38       float arx = fabsf (rx);
  39       /* Avoid incorrect exceptions from libgcc conversions (as of GCC
  40          5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>.  */
  41       if (arx < 0x1p31f)
  42         return (long long int) (long int) rx;
  43       else if (!(arx < 0x1p55f))
  44         return (long long int) (long int) (rx * 0x1p-32f) << 32;
  45       uint32_t i0;
  46       GET_FLOAT_WORD (i0, rx);
  47       int exponent = ((i0 >> 23) & 0xff) - 0x7f;
  48       unsigned long long int mant = (i0 & 0x7fffff) | 0x800000;
  49       mant <<= exponent - 23;
  50       return (long long int) ((i0 & 0x80000000) != 0 ? -mant : mant);
  51     }
  52 #endif
  53 }
  54 libm_alias_float (__llrint, llrint)