Subversion Repositories openrisc

#include "quadmath-imp.h"

#include <math.h>

#include <float.h>

__float128

sqrtq (const __float128 x)

{

  __float128 y;

  int exp;

  if (x == 0)

    return x;

  if (isnanq (x))

    return x;

  if (x < 0)

    return nanq ("");

  if (x <= DBL_MAX && x >= DBL_MIN)

  {

    /* Use double result as starting point.  */

    y = sqrt ((double) x);

    /* Two Newton iterations.  */

    y -= 0.5q * (y - x / y);

    y -= 0.5q * (y - x / y);

    return y;

  }

#ifdef HAVE_SQRTL

  if (x <= LDBL_MAX && x >= LDBL_MIN)

  {

    /* Use long double result as starting point.  */

    y = sqrtl ((long double) x);

    /* One Newton iteration.  */

    y -= 0.5q * (y - x / y);

    return y;

  }

#endif

  /* If we're outside of the range of C types, we have to compute

     the initial guess the hard way.  */

  y = frexpq (x, &exp);

  if (exp % 2)

    y *= 2, exp--;

  y = sqrt (y);

  y = scalbnq (y, exp / 2);

  /* Two Newton iterations.  */

  y -= 0.5q * (y - x / y);

  y -= 0.5q * (y - x / y);

  return y;

}