Getting at the bits of a 32-bit integer

[Jesper Ribbe]

Grant Edwards wrote:

 >
<snip>

> 
> 
> That looks handy.
> 
> The other thing that looks very useful is a module posted a few
> weeks back that impliments fixed-length numbers.  In addition
> to manipulating individual bits, one often needs to do
> operations on binary, two's compliment numbers of known, fixed
> lengths.
> 

I'm very interested in this module which implements fixed-length 
integers. Do you perhaps have some reference to it? I tried to google 
for it, but couldn't come up with distinct enough keywords.

TIA
Jesper