source: trunk/minix/lib/gnu/ieee_float/modf.c@ 9

/*
libc/ieee_float/modf.c

Created:        Oct 14, 1993 by Philip Homburg <philip@cs.vu.nl>

Implementation of modf that directly manipulates the exponent bits in an
ieee float
*/

#include <sys/types.h>
#include <math.h>

#include "ieee_float.h"

double modf(value, iptr)
double value;
double *iptr;
{
        struct f64 *f64p;
        double tmp;
        int exp;
        int mask_bits;
        u32_t mant;

        f64p= (struct f64 *)&value;

        exp= F64_GET_EXP(f64p);
        exp -= F64_EXP_BIAS;
        if (exp < 0)
        {
                *iptr= 0;
                return value;
        }
        mask_bits= 52-exp;
        if (mask_bits <= 0)
        {
                *iptr= value;
                return 0;
        }
        tmp= value;
        if (mask_bits >= 32)
        {
                F64_SET_MANT_LOW(f64p, 0);
                mask_bits -= 32;
                mant= F64_GET_MANT_HIGH(f64p);
                mant &= ~((1 << mask_bits)-1);
                F64_SET_MANT_HIGH(f64p, mant);
        }
        else
        {
                mant= F64_GET_MANT_LOW(f64p);
                mant &= ~((1 << mask_bits)-1);
                F64_SET_MANT_LOW(f64p, mant);
        }
        *iptr= value;
        return tmp-value;
}

/*
 * $PchId: modf.c,v 1.3 1996/02/22 21:01:39 philip Exp $
 */