FP_INIT_ROUNDMODE;
FP_UNPACK_Q (X, x);
FP_SQRT_Q (Y, X);
FP_PACK_Q (y, Y);
FP_HANDLE_EXCEPTIONS;
return y;
#else
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
{
long double xl = (long double) x;
if (xl <= LDBL_MAX && xl >= LDBL_MIN)
{
/* Use long double result as starting point. */
y = (__float128) sqrtl (xl);
/* 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;
#endif
}
