Re: Recode to Play MP3?

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

On May 28, 5:26 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:

> Since you move the data back and forth, the page last written is
> the page next read--perfect.  Moving from page 0 to a page 0 mod 8K
> away conflicts perfectly, so if data were *repeatedly* moved from
> page 0, but not back and forth, every load would be a cache miss!
>
> Doing that experiment, with the second copy loop changed to re-copy
> page 0 to $20xx, results in a time of 8.1sec--almost twice as long.
>
> In this case, the cache only benefits code fetching, not data access.
> But since most 6502 activity is code fetching, it's still pretty fast!

8.1 sec is a big drop. It makes no difference at all to the Transwarp
(except for the aforementioned speed drop writing to video areas).

I would suppose that this would take considerably longer at 4Mhz, so
my feeling that the Transwarp is slightly faster for block copies than
the Zip 4Mhz probably holds.

One thing is for sure, any delusions I had about a double-speed
Transwarp being the ideal accelerator performance wise have well and
truly evaporated :-)

Matt