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glibc  2.9
Functions
s_llround.c File Reference
#include <math.h>
#include "math_private.h"
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Functions

long long int __llround (double x)

Function Documentation

long long int __llround ( double  x)

Definition at line 27 of file s_llround.c.

{
  int32_t j0;
  u_int32_t i1, i0;
  long long int result;
  int sign;

  EXTRACT_WORDS (i0, i1, x);
  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
  sign = (i0 & 0x80000000) != 0 ? -1 : 1;
  i0 &= 0xfffff;
  i0 |= 0x100000;

  if (j0 < 20)
    {
      if (j0 < 0)
       return j0 < -1 ? 0 : sign;
      else
       {
         i0 += 0x80000 >> j0;

         result = i0 >> (20 - j0);
       }
    }
  else if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
    {
      if (j0 >= 52)
       result = (((long long int) i0 << 32) | i1) << (j0 - 52);
      else
       {
         u_int32_t j = i1 + (0x80000000 >> (j0 - 20));
         if (j < i1)
           ++i0;

         if (j0 == 20)
           result = (long long int) i0;
         else
           result = ((long long int) i0 << (j0 - 20)) | (j >> (52 - j0));
       }
    }
  else
    {
      /* The number is too large.  It is left implementation defined
        what happens.  */
      return (long long int) x;
    }

  return sign * result;
}

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