Re: Apple 2 benchmark?

[mdj <mdj.mdj@gmail.com>]

On Sep 4, 11:37 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> Alex Freed wrote:
> > After reading some posts about the different accelerators
> > I wonder if there is a program to test how fast a particular
> > accelerator really is.
>
> > I don't have any commercial accelerators but I want to
> > synthesize my FPGApple for a Virtex-4 chip and see what
> > kind of an EFFECTIVE  clock rate I can get out of it.
>
> The problem with using benchmarks to gauge speedup is that
> all it measures is speedup of that benchmark--and that can
> vary pretty widely with different benchmarks and different
> accelerator architectures--for example, caching.
>
> The simplest and least demanding benchmark is a simple
> FOR-NEXT loop with a large enough count to allow easy
> timing.  (Or two nested, if your machine is *that* fast!)
>
> The next step in complexity and specificity is to insert
> "typical" computations into the FOR loop.  Some people like
> addition and subtraction and IF statements, since they are
> the bulk of most processor-bound computation.
>
> If you throw in trig functions and SQR, then you'll really
> slow an Apple II down, because not only are the floating-point
> software-intensive, but the Applesoft implementations of them
> are quite inefficient--but they're compact.  ;-)

The first program I wrote that made use of the Apple IIe's Auxiliary
memory loaded a large lookup table for SIN(0-PI) into it. This made a
graph plotting package I'd written go from painful to quite pleasant
when computing trig functions :-)

Matt