On Saturday, January 20, 2007 @ 6:42 AM, Carlos Robinson wrote: >The Saturday 2007-01-20 at 11:26 +0100, Theo v. Werkhoven wrote:
>> > > Well, my instructors in the early '70's told me that a byte was >> > > analogous to "bite" -- not the smallest "bit" accessible, but smaller >> > > than the full-size "word" of most architectures of the time. And some >> > > architectures do allow you direct access to a bit. >> >> Why only some? >> Aren't shift- and logical operations part of all CPU architectures? >That's not direct access to a bit, IMO. Direct access would be an >operation that would load into a register a certain bit, or another that >would compare directly to a certain bit in a byte in memory (in one op). I >have never seen it, though. Well, on the second point I think there is the capability of doing a compare under mask where you mask all of the bits except the one you want to compare against. You still load a full word into memory though, even though you're only comparing against one bit. At least that's the way I understand it. >- -- >Cheers, > Carlos E. R. Greg Wallace -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
