/* @(#)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)
{
        int32_t hx,hy,ix,iy;
        u_int32_t lx,ly;
        int32_t esx,esy;

        GET_LDOUBLE_WORDS(esx,hx,lx,x);
        GET_LDOUBLE_WORDS(esy,hy,ly,y);
        ix = esx&0x7fff;                /* |x| */
        iy = esy&0x7fff;                /* |y| */

        if (((ix==0x7fff)&&(((hx&0x7fffffff)|lx)!=0)) ||   /* x is nan */
            ((iy==0x7fff)&&(((hy&0x7fffffff)|ly)!=0)))     /* y is nan */
           return x+y;
        if(x==y) return y;              /* x=y, return y */
        if((ix|hx|lx)==0) {                     /* x == 0 */
            volatile long double u;
            SET_LDOUBLE_WORDS(x,esy&0x8000,0,1);/* return +-minsubnormal */
            u = x;
            u = u * u;                          /* raise underflow flag */
            return x;
        }
        if(esx>=0) {                    /* x > 0 */
            if(esx>esy||((esx==esy) && (hx>hy||((hx==hy)&&(lx>ly))))) {
              /* x > y, x -= ulp */
                if(lx==0) {
                    if ((hx&0x7fffffff)==0) esx -= 1;
                    hx = (hx - 1) | (hx & 0x80000000);
                }
                lx -= 1;
            } else {                            /* x < y, x += ulp */
                lx += 1;
                if(lx==0) {
                    hx = (hx + 1) | (hx & 0x80000000);
                    if ((hx&0x7fffffff)==0) esx += 1;
                }
            }
        } else {                                /* x < 0 */
            if(esy>=0||(esx>esy||((esx==esy)&&(hx>hy||((hx==hy)&&(lx>ly)))))){
              /* x < y, x -= ulp */
                if(lx==0) {
                    if ((hx&0x7fffffff)==0) esx -= 1;
                    hx = (hx - 1) | (hx & 0x80000000);
                }
                lx -= 1;
            } else {                            /* x > y, x += ulp */
                lx += 1;
                if(lx==0) {
                    hx = (hx + 1) | (hx & 0x80000000);
                    if ((hx&0x7fffffff)==0) esx += 1;
                }
            }
        }
        esy = esx&0x7fff;
        if(esy==0x7fff) return x+x;             /* overflow  */
        if(esy==0) {
            volatile long double u = x*x;       /* underflow */
            if(u==x) {
                SET_LDOUBLE_WORDS(x,esx,hx,lx);
                return x;
            }
        }
        SET_LDOUBLE_WORDS(x,esx,hx,lx);
        return x;
}
DEF_STD(nextafterl);
MAKE_UNUSED_CLONE(nexttowardl, nextafterl);