Re: [office-formula] BITAND, etc. - what about bit limits/signbit? Gnumeric folks, willing to change what they do?

["Andreas J. Guelzow" <aguelzow@math.concordia.ab.ca>]

On Fri, 2006-01-09 at 11:47 -0400, David A. Wheeler wrote:
> I've been fiddling with Gnumeric, and have found an unwelcome and
> undocumented "feature" of Gnumeric's BITAND, BITOR, etc.
> Basically, they presume that all values are 32-bit SIGNED values,
> and they only produce 32-bit signed values.
> Bit position 32 (counting from 1=LSB) is always the sign bit,
> which fundamentally limits the largest size they can handle.
> 
> That's really annoying.  As computers get bigger, I'd hate to be
> limited to 32-bit values.  Indeed, I think most implementations
> use IEEE 754 doubles, so you can get more bits RIGHT NOW,
> and 48 bits are actually very useful.  And getting negative numbers
> when bit position 32 is 1 is not always what you want!
> 
> So we have three options:
> 1. Spec what Gnumeric does (w/sign bit).  But this will greatly constrain
>     future implementations in an unfriendly way.  I don't like that option.
> 2. Spec that what Gnumeric does is wrong in this case - don't have
>     "sign" values in any particular position.  Then require
>     that positive values be supported up to some large value
>     (say 2^48-1, or 2^50-1).  This would impose a change
>     on Gnumeric that they may think is not appropricate.
>     Gnumeric folks, any comment?
> 3. Add a "portable constraint", saying that they take
>     values 0 <= N <= 2^31-1.  Then what happens
>     beyond those ranges is implementation-defined.
> 
> Number 3 is the easiest.  Number 2 is the cleanest long-term.
> 
> Comments? Thoughts?  I'd like to hear from the Gnumeric
> developers in particular, but I'd like to hear from anyone.

What does MS Excel do?

Andreas