/* @(#)s_nextafter.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.
 * ====================================================
 */

/* IEEE functions
 *      nextafterl(x,y)
 *      return the next machine floating-point number of x in the
 *      direction toward y.
 *   Special cases:
 */

#include <math.h>

#include "math_private.h"

long double
nextafterl(long double x, long double y)
{
        int64_t hx,hy,ix,iy;
        u_int64_t lx,ly;

        GET_LDOUBLE_WORDS64(hx,lx,x);
        GET_LDOUBLE_WORDS64(hy,ly,y);
        ix = hx&0x7fffffffffffffffLL;           /* |x| */
        iy = hy&0x7fffffffffffffffLL;           /* |y| */

        if(((ix>=0x7fff000000000000LL)&&((ix-0x7fff000000000000LL)|lx)!=0) ||   /* x is nan */
           ((iy>=0x7fff000000000000LL)&&((iy-0x7fff000000000000LL)|ly)!=0))     /* y is nan */
           return x+y;
        if(x==y) return y;              /* x=y, return y */
        if((ix|lx)==0) {                        /* x == 0 */
            volatile long double u;
            SET_LDOUBLE_WORDS64(x,hy&0x8000000000000000ULL,1);/* return +-minsubnormal */
            u = x;
            u = u * u;                          /* raise underflow flag */
            return x;
        }
        if(hx>=0) {                     /* x > 0 */
            if(hx>hy||((hx==hy)&&(lx>ly))) {    /* x > y, x -= ulp */
                if(lx==0) hx--;
                lx--;
            } else {                            /* x < y, x += ulp */
                lx++;
                if(lx==0) hx++;
            }
        } else {                                /* x < 0 */
            if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */
                if(lx==0) hx--;
                lx--;
            } else {                            /* x > y, x += ulp */
                lx++;
                if(lx==0) hx++;
            }
        }
        hy = hx&0x7fff000000000000LL;
        if(hy==0x7fff000000000000LL) return x+x;/* overflow  */
        if(hy==0) {
            volatile long double u = x*x;       /* underflow */
        }
        SET_LDOUBLE_WORDS64(x,hx,lx);
        return x;
}
DEF_STD(nextafterl);
MAKE_UNUSED_CLONE(nexttowardl, nextafterl);