/* s_modfl.c -- long double version of s_modf.c.

 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.

 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

#if defined(LIBM_SCCS) && !defined(lint)

static char rcsid[] = "$NetBSD: $";

#endif

/*

 * modfl(long double x, long double *iptr)

 * return fraction part of x, and return x's integral part in *iptr.

 * Method:

 *	Bit twiddling.

 *

 * Exception:

 *	No exception.

 */

#include <math.h>

#include <math_private.h>

#include <math_ldbl_opt.h>

static const long double one = 1.0;

long double __modfl(long double x, long double *iptr)

{

	int64_t i0,i1,j0;

	uint64_t i;

	double xhi, xlo;

	ldbl_unpack (x, &xhi, &xlo;;

	EXTRACT_WORDS64 (i0, xhi);

	EXTRACT_WORDS64 (i1, xlo);

	i1 &= 0x000fffffffffffffLL;

	j0 = ((i0>>52)&0x7ff)-0x3ff;	/* exponent of x */

	if(j0<52) {			/* integer part in high x */

	    if(j0<0) {			/* |x|<1 */

		/* *iptr = +-0 */

		INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);

		*iptr = xhi;

		return x;

	    } else {

		i = (0x000fffffffffffffLL)>>j0;

		if(((i0&i)|(i1&0x7fffffffffffffffLL))==0) {		/* x is integral */

		    *iptr = x;

		    /* return +-0 */

		    INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);

		    x = xhi;

		    return x;

		} else {

		    INSERT_WORDS64 (xhi, i0&(~i));

		    *iptr = xhi;

		    return x - *iptr;

		}

	    }

	} else if (j0>103) {		/* no fraction part */

	    *iptr = x*one;

	    /* We must handle NaNs separately.  */

	    if ((i0 & 0x7fffffffffffffffLL) > 0x7ff0000000000000LL)

	      return x*one;

	    /* return +-0 */

	    INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);

	    x = xhi;

	    return x;

	} else {			/* fraction part in low x */

	    i = -1ULL>>(j0-52);

	    if((i1&i)==0) { 		/* x is integral */

		*iptr = x;

		/* return +-0 */

		INSERT_WORDS64 (xhi, i0&0x8000000000000000ULL);

		x = xhi;

		return x;

	    } else {

		INSERT_WORDS64 (xhi, i0);

		INSERT_WORDS64 (xlo, i1&(~i));

		*iptr = ldbl_pack (xhi, xlo);

		return x - *iptr;

	    }

	}

}

#if IS_IN (libm)

long_double_symbol (libm, __modfl, modfl);

#else

long_double_symbol (libc, __modfl, modfl);

#endif