[squeak-dev] Integer>>bitAt: (was [ANN] Kernel methods license audit)

nicolas cellier ncellier at ifrance.com
Fri Mar 21 00:17:50 UTC 2008


nicolas cellier a écrit :
>
> However, looking at the source, apart accessors, some methods will 
> hardly ever change, like:
> Integer>>bitInvert
>     ^-1-self
> 
> There is no added value in such method but very obvious algorithm:
> two complement: bitinvert the digits, and add 1
> => bitInvert: take two complement, and subtract 1
> 
> The trick is not here, it is in pretending LargeNegativeInteger are 
> stored in two complements, what they are not...
> So the trick is in all the bitOr:, bitAnd:, bitXor:, bitShift: 
> implementations, as a whole.
> 

By the way, why do we lack a Integer>>bitAt: ?
http://bugs.squeak.org/view.php?id=6985

Nicolas




More information about the Squeak-dev mailing list