fbCombineDisjointInPart (CARD8 a, CARD8 b)
{
    /* max (1-(1-b)/a,0) */
    /*  = - min ((1-b)/a - 1, 0) */
    /*  = 1 - min (1, (1-b)/a) */

    b = ~b;		    /* 1 - b */
    if (b >= a)		    /* 1 - b >= a -> (1-b)/a >= 1 */
	return 0;	    /* 1 - 1 */
    return ~FbIntDiv(b,a);  /* 1 - (1-b) / a */
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.