modf.c

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/* @(#)s_modf.c 1.3 95/01/18 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunSoft, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */
#define modfl _dummy_modfl
#include <precomp.h>
#undef modfl
 
//static const double one = 1.0;
 
 
 
long double modfl(long double __x, long double *__i)
{
    union
    {
        long double*   __x;
        long_double_s*   x;
    } x;
    union
    {
        long double*    __i;
        long_double_s* iptr;
    } iptr;
 
    int j0;
    unsigned int i;
 
    x.__x = &__x;
    iptr.__i = __i;
 
 
    j0 = x.x->exponent - 0x3fff;  /* exponent of x */
 
    if(j0<32) {                     /* integer part in high x */
        if(j0<0) {                  /* |x|<1 */
            *__i = 0.0L;
            iptr.iptr->sign = x.x->sign;
            return __x;
        } else {
 
            i = ((unsigned int)(0xffffffff))>>(j0+1);
            if ( x.x->mantissal == 0 && (x.x->mantissal & i) == 0 ) {
                *__i =  __x;
                __x = 0.0L;
                x.x->sign = iptr.iptr->sign;
                return __x;
            }
            iptr.iptr->sign = x.x->sign;
            iptr.iptr->exponent = x.x->exponent;
            iptr.iptr->mantissah = x.x->mantissah&((~i));
            iptr.iptr->mantissal = 0;
 
            return __x - *__i;
        }
    } else if (j0>63) {             /* no fraction part */
        *__i = __x;
        if (  _isnanl(__x) ||  _isinfl(__x)  )
            return __x;
 
        __x = 0.0L;
        x.x->sign = iptr.iptr->sign;
        return __x;
    } else {                        /* fraction part in low x */
 
        i = ((unsigned int)(0xffffffff))>>(j0-32);
        if ( x.x->mantissal == 0 ) {
            *__i =  __x;
            __x = 0.0L;
            x.x->sign = iptr.iptr->sign;
            return __x;
        }
        iptr.iptr->sign = x.x->sign;
        iptr.iptr->exponent = x.x->exponent;
        iptr.iptr->mantissah = x.x->mantissah;
        iptr.iptr->mantissal = x.x->mantissal&(~i);
 
        return __x - *__i;
    }
}