[coyotos-dev] BigNum.cxx buglet?

[Jonathan S. Shapiro]

On Sun, 2007-09-30 at 20:34 +0200, Thomas Stratmann wrote:

> 
> Having corrected myself, my original description of the error should 
> make sense now. (look ten lines above for
> 
>      q.len = (dividend.len - divisor.len + 1);
> 
> and think of the case divident.len==1, divident.oneDigit==255,
> divisor.len==2, divident's digits being 0, 10 to represent "10")

I don't think that can happen, because the test using vu_cmp() above
this point... Oh. I see. Yes. The problem is the vector length rather
than the respective magnitudes. Given leading zeroes the right thing
here is to use max(dividend.len, divisor.len).

Concur? [I don't want to blow out three updates today, so might as well ask first.]

> This means that the "q.len =..." line is a bug because the leading zero 
> case is not taken care of, right?

Yes.
-- 
Jonathan S. Shapiro
Managing Director
The EROS Group, LLC
www.coyotos.org, www.eros-os.org