adtools/clib2

/*
 * $Id: math_modf.c,v 1.7 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.
 *
 *
 * 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

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

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

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

#if defined(FLOATING_POINT_SUPPORT)

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

#if defined(M68881_FLOATING_POINT_SUPPORT)

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

INLINE STATIC const double
__modf(double x,double *nptr)
{
    double result;
    double temp;

    __asm ("fintrz%.x %1,%0"
           : "=f" (temp)    /* integer-valued float */
           : "f" (x));

    (*nptr) = temp;

    result = x - temp;

    return(result);
}

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

#else

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

static const double one = 1.0;

INLINE STATIC double
__modf(double x, double *iptr)
{
    LONG i0,i1,j0;
    ULONG i;
    EXTRACT_WORDS(i0,i1,x);
    j0 = ((i0>>20)&0x7ff)-0x3ff;    /* exponent of x */
    if(j0<20) {            /* integer part in high x */
        if(j0<0) {            /* |x|<1 */
            INSERT_WORDS(*iptr,i0&0x80000000,0);    /* *iptr = +-0 */
        return x;
        } else {
        i = (0x000fffff)>>j0;
        if(((i0&i)|i1)==0) {        /* x is integral */
            ULONG high;
            *iptr = x;
            GET_HIGH_WORD(high,x);
            INSERT_WORDS(x,high&0x80000000,0);    /* return +-0 */
            return x;
        } else {
            INSERT_WORDS(*iptr,i0&(~i),0);
            return x - *iptr;
        }
        }
    } else if (j0>51) {        /* no fraction part */
        ULONG high;
        *iptr = x*one;
        GET_HIGH_WORD(high,x);
        INSERT_WORDS(x,high&0x80000000,0);    /* return +-0 */
        return x;
    } else {            /* fraction part in low x */
        i = ((ULONG)(0xffffffff))>>(j0-20);
        if((i1&i)==0) {         /* x is integral */
            ULONG high;
        *iptr = x;
        GET_HIGH_WORD(high,x);
        INSERT_WORDS(x,high&0x80000000,0);    /* return +-0 */
        return x;
        } else {
            INSERT_WORDS(*iptr,i0,i1&(~i));
        return x - *iptr;
        }
    }
}

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

#endif /* M68881_FLOATING_POINT_SUPPORT */

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

double
modf(double x,double *nptr)
{
    double result;

    assert( nptr != NULL );

    #if defined(CHECK_FOR_NULL_POINTERS)
    {
        if(nptr == NULL)
        {
            __set_errno(EFAULT);

            result = __get_huge_val();
            goto out;
        }
    }
    #endif /* CHECK_FOR_NULL_POINTERS */

    result = __modf(x,nptr);

 out:

    return(result);
}

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

#endif /* FLOATING_POINT_SUPPORT */