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glibc  2.9
Functions | Variables
s_roundl.c File Reference
#include <math.h>
#include "math_private.h"
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Functions

long double __roundl (long double x)

Variables

static const long double huge = 1.0E4930L

Function Documentation

long double __roundl ( long double  x)

Definition at line 31 of file s_roundl.c.

{
  int32_t j0;
  u_int64_t i1, i0;

  GET_LDOUBLE_WORDS64 (i0, i1, x);
  j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
  if (j0 < 31)
    {
      if (j0 < 0)
       {
         if (huge + x > 0.0)
           {
             i0 &= 0x8000000000000000ULL;
             if (j0 == -1)
              i0 |= 0x3fff000000000000LL;
             i1 = 0;
           }
       }
      else
       {
         u_int64_t i = 0x0000ffffffffffffLL >> j0;
         if (((i0 & i) | i1) == 0)
           /* X is integral.  */
           return x;
         if (huge + x > 0.0)
           {
             /* Raise inexact if x != 0.  */
             i0 += 0x0000800000000000LL >> j0;
             i0 &= ~i;
             i1 = 0;
           }
       }
    }
  else if (j0 > 111)
    {
      if (j0 == 0x4000)
       /* Inf or NaN.  */
       return x + x;
      else
       return x;
    }
  else
    {
      u_int64_t i = -1ULL >> (j0 - 48);
      if ((i1 & i) == 0)
       /* X is integral.  */
       return x;

      if (huge + x > 0.0)
       {
         /* Raise inexact if x != 0.  */
         u_int64_t j = i1 + (1LL << (111 - j0));
         if (j < i1)
           i0 += 1;
         i1 = j;
       }
      i1 &= ~i;
    }

  SET_LDOUBLE_WORDS64 (x, i0, i1);
  return x;
}

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Variable Documentation

const long double huge = 1.0E4930L [static]

Definition at line 27 of file s_roundl.c.