[Coco] technical assembler question

[Robert Gault]

Bob Devries wrote:
> dear friends,
> 
> I'm doing some writing in assembler for RSDOS (DECB). I don't do this 
> often, you understand, so I've got a question:
> 
> When checking for a BREAK key, is it necessary yo do multiple reads of 
> the POLCAT routine to ensure the key is not missed? At the moment i have 
> this code:
> 
> jsr [POLCAT]
> beq dskcont ;no key pressed, continue
> cmpa #BREAK ;that's #$03
> bne dskcont ;on BREAK, fall through to exit routine
> 
> Should I loop through that a few times to be sure I don't miss it or 
> will that slow the programme down too much.
> 
> What do the "experts" do in this case?
> 

Probably depends on how often your code will do the BREAK test. You 
would not want several seconds to go by but the user is not likely to 
notice the difference of a poll every second vrs VSYNC intervals.