[iyonix-support] Re: Iyonix technical questions
- From: Xavier Tardy <xatardy@xxxxxxxxxx>
- To: iyonix-support@xxxxxxxxxxxxx
- Date: Mon, 28 Jul 2008 10:36:16 +0200
Xavier Tardy a écrit :
Hello everybody.
I've got a question, since I'd like to restart programming from
scratch a game I had programmed 15 years ago
for the Archimedes.
Although very good at the time, I'd like it to be even better for the
Iyonix, so here is my concern.
At the time, I didn't use any piece of code under interrupt (I didn't
program the MOD player) but this time I'd like to have a try at it.
And here is why.
As you know in a game you usually display a frame while 'creating' the
next one you'll make visible
after the electron beam reached the end of the screen, which is good
for flicker free display and synchronisation.
At the end of the usual things you've got to do to create the next
frame, you wait for Vsync (MOV R0,#19 SWI &19)
and then ask the video controller to show what has just been done,
during the coming screen refresh.
But well you can lose a lot of time, doing nothing but waiting,
between the end of the execution of your code, and the Vsync event
you're waiting for to switch
the bank screens, and start it all again.
For this reason I would like to use this time for non critical
operations, maintenance, like for example re organizing the memory
used by my code.
Unfortunately, I just don't know how to write some decent code under
interrupt, and it's what I need.
I would start this code under interrupt, and stop it right after the
Vsync event occured, setting right afterwards a value in a register
that the code under interrupt
would check to end correctly what it is up to.
So : help needed.
Thank you.
Xavier.
Hello again.
Don't lose your time answering me I've just found what I wanted and with
a better algorithm than the one I spoke about.
Kind regards,
Xavier.
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