/* @(#)s_modf.c 5.1 93/09/24 */
/*
 * ====================================================
 * 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.
 * ====================================================
 */

/*
 * 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"

static const long double one = 1.0;

long double
modfl(long double x, long double *iptr)
{
        int32_t i0,i1,jj0;
        u_int32_t i,se;
        GET_LDOUBLE_WORDS(se,i0,i1,x);
        jj0 = (se&0x7fff)-0x3fff;       /* exponent of x */
        if(jj0<32) {                    /* integer part in high x */
            if(jj0<0) {                 /* |x|<1 */
                SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */
                return x;
            } else {
                i = (0x7fffffff)>>jj0;
                if(((i0&i)|i1)==0) {            /* x is integral */
                    *iptr = x;
                    SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
                    return x;
                } else {
                    SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0);
                    return x - *iptr;
                }
            }
        } else if (jj0>63) {            /* no fraction part */
            *iptr = x*one;
            /* We must handle NaNs separately.  */
            if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1))
              return x*one;
            SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
            return x;
        } else {                        /* fraction part in low x */
            i = ((u_int32_t)(0x7fffffff))>>(jj0-32);
            if((i1&i)==0) {             /* x is integral */
                *iptr = x;
                SET_LDOUBLE_WORDS(x,se&0x8000,0,0);     /* return +-0 */
                return x;
            } else {
                SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i));
                return x - *iptr;
            }
        }
}