Subject: Re: bcopy, bzero, copypage, and zeropage
To: Jason Thorpe <thorpej@nas.nasa.gov>
From: Chris G Demetriou <Chris_G_Demetriou@auchentoshan.pdl.cs.cmu.edu>
List: tech-kern
Date: 12/14/1996 13:31:33
> This eliminates unnecessary code size and overhead from indirect
> function calls in the critical path.
Oh, and while i'm at it:
One some architectures, there's really no overhead difference between
a 'direct' and 'indirect' function call. There's always cpu-cycle
overhead for comparisons and branches, not to mention the additional
memory load that they can cause (test
Code size is a good argument for single-function implementations, but
i'm not completely convinced that even on the m68k that the "indirect
function call" one is, for "generic" implementations. (See my
previous message for a good way to remove all potential overhead for
"specific" implementations.)
On some architectures, all you're left with is code size. While
that's a good argument, well, welcome to the wonderful world of
space-time tradeoffs. 8-)
chris