/* @(#)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
 *      nexttowardf(x,y)
 *      return the next machine floating-point number of x in the
 *      direction toward y.
 * This is for machines which use the same binary type for double and
 * long double.
 *   Special cases:
 */

#include <math.h>
#include <float.h>

#include "math_private.h"

float
nexttowardf(float x, long double y)
{
        int32_t hx,hy,ix,iy;
        u_int32_t ly;

        GET_FLOAT_WORD(hx,x);
        EXTRACT_WORDS(hy,ly,y);
        ix = hx&0x7fffffff;             /* |x| */
        iy = hy&0x7fffffff;             /* |y| */

        if((ix>0x7f800000) ||                              /* x is nan */
           ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0))    /* y is nan */
           return x+y;
        if((long double) x==y) return y;        /* x=y, return y */
        if(ix==0) {                             /* x == 0 */
            volatile float u;
            SET_FLOAT_WORD(x,(u_int32_t)(hy&0x80000000)|1);/* return +-minsub*/
            u = x;
            u = u * u;                          /* raise underflow flag */
            return x;
        }
        if(hx>=0) {                             /* x > 0 */
            if(hy<0||(ix>>23)>(iy>>20)-0x380
               || ((ix>>23)==(iy>>20)-0x380
                   && (ix&0x7fffff)>(((hy<<3)|(ly>>29))&0x7fffff)))     /* x > y, x -= ulp */
                hx -= 1;
            else                                /* x < y, x += ulp */
                hx += 1;
        } else {                                /* x < 0 */
            if(hy>=0||(ix>>23)>(iy>>20)-0x380
               || ((ix>>23)==(iy>>20)-0x380
                   && (ix&0x7fffff)>(((hy<<3)|(ly>>29))&0x7fffff)))     /* x < y, x -= ulp */
                hx -= 1;
            else                                /* x > y, x += ulp */
                hx += 1;
        }
        hy = hx&0x7f800000;
        if(hy>=0x7f800000) {
          x = x+x;      /* overflow  */
          return x;
        }
        if(hy<0x00800000) {
            volatile float u = x*x;             /* underflow */
            if(u==x) {
                SET_FLOAT_WORD(x,hx);
                return x;
            }
        }
        SET_FLOAT_WORD(x,hx);
        return x;
}