-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Saturday 2007-01-20 at 14:41 -0600, Greg Wallace wrote:
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.
Not quite, using masks we still operate on the full byte or word. It's a logic trick, only the "target" bit will modify the output. But the operation is on the whole. That is, we can make decissions based on the state of a certain bit, for instance, but the procesor can not directly access a bit. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFsrbjtTMYHG2NR9URAqNWAJ9N5barBTZ3OFXAAoB5B3Do0NRMgACaAygO BrwbHiB5nhN+HNOY1TM08GM= =shgR -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org