[iyonix-support] Re: Iyonix technical questions

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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