On 4/22/07, Petter Urkedal <[EMAIL PROTECTED]> wrote:
I find the (src, src, dst)-ordered assembly easier myself, since reading
I've programmed assembly for both types to the point that it doesn't bother me anymore. I figure out which order I'm working with, and somehow, I manage to not get confused. Imagine being fluent in both Arabic and Japanese. You don't notice the opposing word orders.
I can't see a way to do 64 bit adds in less that 4 instructions without introducing some sort of status register which needs to be saved in case of async control flow.
IIRC, the way to do a 64-bit add on MIPS involves an add for the lower half, a compare (subtract), a branch, an add for the upper half in the delay slot, and another add that the branch may jump over that increments the upper half in the case of a carry. So 4 or 5 instructions, depending on the carry. I've read about the reasoning process the designers went through when deciding not to include result flags. It has to do with tracking instruction dependencies (what we call hazards). Without flags, the dependencies are restricted mosly to the register file. With flags, you end up having to be too conservative and deal with false dependencies. Y'all really need to read up on this stuff. Patterson and Hennessy. Computer Architecture: A Quantitative Approach. Look them up on Amazon. -- Timothy Normand Miller http://www.cse.ohio-state.edu/~millerti Open Graphics Project _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
