[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Recode to Play MP3?



bieling@terra.es wrote:
On 25 mayo, 21:43, "Michael J. Mahon" <mjma...@aol.com> wrote:

Steven Hirsch wrote:

biel...@terra.es wrote:

I'm not sure that an accelerator will cache the c800.cfff range

The ZipChip (II/IIe) certainly does not, since it's not smart enough to
know when or whether that region has been switched out underneath it. To work around that, you can clone the transfer loop into the stack page
and run it full-clip from there.

Take a look at the sources for the Ramfast host ROM that are, um,
floating around for an example of how this can be done.

Which, for me, raises the question of what "high water marks" are for
the stack under various conditions...

It would be easy enough to do the experiment by initializing the stack
to an obvious mark byte, but I've never seen any studies that would
suggest how much of page 1 can be considered "free" at, say, ProDOS READ
or WRITE time.

I'd begin to get uncomfortable around 32 bytes...



What about the keyboard buffer ?
IIRC sometimes it's used for things like that.
Probably by the time the disk xfers start, the keyboard buffer has
been scanned already, and probably it won't be polled until after the
xfers has taken place... ?

Good point.  ProDOS already appropriated the second half of page 2
for a pathname buffer (which is probably also free at the time of
data transfer--unless error handling uses it).

-michael

NadaNet file server for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."