adtools/clib2

/*
 * $Id: math_nextafterf.c,v 1.3 2006-01-08 12:04:24 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * PowerPC math library based in part on work by Sun Microsystems
 * 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.
 *
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

#ifndef _MATH_HEADERS_H
#include "math_headers.h"
#endif /* _MATH_HEADERS_H */

/****************************************************************************/

#if defined(FLOATING_POINT_SUPPORT)

/****************************************************************************/

float
nextafterf(float x, float y)
{
    long hx,hy,ix,iy;

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

    if((ix>0x7f800000) ||   /* x is nan */
       (iy>0x7f800000))     /* y is nan */
       return (float)(x+y);
    if(x==y) return x;        /* x=y, return x */
    if(ix==0) {                /* x == 0 */
        SET_FLOAT_WORD(x,(hy&0x80000000U)|1);/* return +-minsubnormal */
        y = x*x;
        if(y==x) return y; else return x;    /* raise underflow flag */
    }
    if(hx>=0) {                /* x > 0 */
        if(hx>hy) {                /* x > y, x -= ulp */
        hx -= 1;
        } else {                /* x < y, x += ulp */
        hx += 1;
        }
    } else {                /* x < 0 */
        if(hy>=0||hx>hy){            /* x < y, x -= ulp */
        hx -= 1;
        } else {                /* x > y, x += ulp */
        hx += 1;
        }
    }
    hy = hx&0x7f800000;
    if(hy>=0x7f800000) return (float)(x+x);    /* overflow  */
    if(hy<0x00800000) {        /* underflow */
        y = x*x;
        if(y!=x) {        /* raise underflow flag */
            SET_FLOAT_WORD(y,hx);
        return y;
        }
    }
    SET_FLOAT_WORD(x,hx);
    return x;
}

/****************************************************************************/

#endif /* FLOATING_POINT_SUPPORT */