Search found 54 matches

by zx81user
Mon Mar 25, 2013 9:40 pm
Forum: Development
Topic: timing interrupt routine
Replies: 10
Views: 4030

Re: timing interrupt routine

What is the physical address of "FRAMES"?
by zx81user
Mon Mar 25, 2013 12:17 pm
Forum: Development
Topic: timing interrupt routine
Replies: 10
Views: 4030

Re: timing interrupt routine

ok, that is a lot more than I initially thought :-). I found a clock program, I think it will use the same trick so I will disassemble that and see what is exactly there. Is there any way to do a smart kind of disassembling of some machine code in a REM statement?
by zx81user
Mon Mar 25, 2013 4:06 am
Forum: Development
Topic: timing interrupt routine
Replies: 10
Views: 4030

Re: timing interrupt routine

I think I found the answer already. If I understand correctly, the IX register contains an interrupt vector that will be called 50 or 60 times per second. By changing this vector to my own routine and ending with a jump to the original vector that should then exactly do what I want. Is it that simpl...
by zx81user
Mon Mar 25, 2013 3:41 am
Forum: Development
Topic: timing interrupt routine
Replies: 10
Views: 4030

timing interrupt routine

Hi All, I cleaned out the garage last weekend and bumped into my good old ZX81! I couldn't dare to throw it out so I thought maybe I can use it for "something", not sure yet what to use it for though! The problem I ran into long time ago is that I couldn't figure out how to get an interrupt at const...