Re: Mockingboard emulator (was: Late night musings...)

[nathan@visi.com (Nathan Mates)]

In article <50gi1v$qpv@seeker.the-hermes.net>,
Geoff Weiss <geoff@seeker.the-hermes.net> wrote:
>Lets see what is wrong with this logic (Nathan gave a half-dozen
>reasons a few posts back).  First of all, you want this code to run in bank 0,
>right?

   Nope, he's said he wants it to run elsewhere. The main problem with
that is that running things outside of bank 0, and using something to
copy the screen out will take something and run it even slower. Even a
mirror of the text screen would take forever. (And doing a video
mirror from within a HB task would take so long that anything else
going a HB take would suffer. Use a HB task to set a flag that your
emulator deals with not from within ain interrupt.) Interpreting the
hires screen to the SHR screen or a window is not something that could
be done with any sort of resemblance of speed. 

   In other words, the main adjective that would describe this is, once
again, SLOW. (I think that 100% emulation with only delta updates to
the screen if and when something does change would be faster.)


>Remember, _every_ memory access instruction that isn't a direct page
>access would be needed to check for access in bank $C0.

   The DP can be used to hit the softswitches just as easily as anything
else. (Not that I know of many that did, but for safety's sake...)

Nathan
--
<*> Nathan Mates http://www.visi.com/~nathan/      <*>
# What are the facts? Again and again and again-- what are the _facts_?
# Shun wishful thinking, avoid opinion, care not what the neighbors
# think-- what are the facts, and to how many decimal places?  -R.A. Heinlein