On Dec 17, 2007, at 19:04 , Cees de Groot wrote:

> On Dec 17, 2007 1:49 PM, Bert Freudenberg <bert at freudenbergs.de>  
> wrote:
>>> 0 bitXnor: 0 -> -1
>>
>> And what exactly is wrong with that?
>>
> err... I'd expect '1' here?

How should that method know you are looking for 1-bit numbers only?  
In your logic

     2r0 bitXnor: 2r0 -> 2r1
     2r00 bitXnor: 2r00 -> 2r11

which would be rather weird, wouldn't it?

-1 in two's complement is an endless string of 1s, so that's the  
Right Thing.

If you want a "fixed-width" number then you can just #bitAnd: with  
the number of bits you like:

-1 bitAnd: 2r1  -> 2r1
-1 bitAnd: 2r11 -> 2r11

- Bert -