Subversion Repositories openrisc_2011-10-31

/* @(#)z_ldexpf.c 1.0 98/08/13 */

/******************************************************************

 * ldexp

 *

 * Input:

 *   d - a floating point value

 *   e - an exponent value

 *

 * Output:

 *   A floating point value f such that f = d * 2 ^ e.

 *

 * Description:

 *   This function creates a floating point number f such that

 *   f = d * 2 ^ e.

 *

 *****************************************************************/

#include <float.h>

#include "fdlibm.h"

#include "zmath.h"

#define FLOAT_EXP_OFFS 127

float

_DEFUN (ldexpf, (float, int),

        float d _AND

        int e)

{

  int exp;

  __int32_t wd;

  GET_FLOAT_WORD (wd, d);

  /* Check for special values and then scale d by e. */

  switch (numtestf (wd))

    {

      case NAN:

        errno = EDOM;

        break;

      case INF:

        errno = ERANGE;

        break;

      case 0:

        break;

      default:

        exp = (wd & 0x7f800000) >> 23;

        exp += e;

        if (exp > FLT_MAX_EXP + FLOAT_EXP_OFFS)

         {

           errno = ERANGE;

           d = z_infinity_f.f;

         }

        else if (exp < FLT_MIN_EXP + FLOAT_EXP_OFFS)

         {

           errno = ERANGE;

           d = -z_infinity_f.f;

         }

        else

         {

           wd &= 0x807fffff;

           wd |= exp << 23;

           SET_FLOAT_WORD (d, wd);

         }

    }

    return (d);

}

#ifdef _DOUBLE_IS_32BITS

double ldexp (double x, int e)

{

  return (double) ldexpf ((float) x, e);

}

#endif /* defined(_DOUBLE_IS_32BITS) */