adtools/clib2

/*
 * $Id: math_floorf.c,v 1.3 2006-01-08 12:04:23 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.
 */

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

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

#if defined(FLOATING_POINT_SUPPORT)

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

static const float huge = 1.0e30;

float
floorf(float x)
{
    LONG i0,j_0;
    ULONG i;
    GET_FLOAT_WORD(i0,x);
    j_0 = ((i0>>23)&0xff)-0x7f;
    if(j_0<23) {
        if(j_0<0) {     /* raise inexact if x != 0 */
        if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
            if(i0>=0) {i0=0;} 
            else if((i0&0x7fffffff)!=0)
            { i0=0xbf800000U;}
        }
        } else {
        i = (0x007fffff)>>j_0;
        if((i0&i)==0) return x; /* x is integral */
        if(huge+x>(float)0.0) {    /* raise inexact flag */
            if(i0<0) i0 += (0x00800000)>>j_0;
            i0 &= (~i);
        }
        }
    } else {
        if(j_0==0x80) return x+x;    /* inf or NaN */
        else return x;        /* x is integral */
    }
    SET_FLOAT_WORD(x,i0);
    return x;
}

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

#endif /* FLOATING_POINT_SUPPORT */