DT-INTs What's legal in an INT handler?

[circuitpro]

My program spends most of it's time in a loop waiting for an interrupt (button presses). Once received, I need to decode 24 buttons and execute the right commands.

My present interrupt handler has a SELECT CASE function in it, with a GOSUB in every case to execute the functions. Is this legit? What are the specifics and restrictions in an interrupt handler?

[Bruce]

With DT_INTS using a PBP type interrupt, pretty much anything goes. I.E. use as many
PBP instructions as you like in the int handler.

That's the really cool part of using DTs' int program. He's done all the work for you.

Just don't GOSUB outside the interrupt handler - or it will go-like-splat...

[circuitpro]

Thanks Bruce. The issue that led me to this question is obviously something else.

I'm using LONG variables for the first time, and have an issue where a bit in a 24-bit LONG is being changed/corrupted by me TOGGLEING another, unrelated BIT variable! I figured the problem is me MISDECLARING my variables OR my interrupt handler. Bit 14 of the LONG variable GRN is being corrupted when I toggle the bit variable SOLO. (If I don't use interrupts, the problem goes away).

My variable declarations are:

RED         VAR     LONG                  
GRN         VAR     LONG                  
BUTTONS     VAR     LONG                  
X           VAR     LONG                   
Y           VAR     BYTE                    
Z           VAR     BYTE                    
RED0        VAR     RED.BYTE0
RED1        VAR     RED.BYTE1
RED2        VAR     RED.BYTE2
GRN0        VAR     GRN.BYTE0
GRN1        VAR     GRN.BYTE1
GRN2        VAR     GRN.BYTE2                
BU0         VAR     BUTTONS.BYTE0           
BU1         VAR     BUTTONS.BYTE1         
BU2         VAR     BUTTONS.BYTE2           
LCD         VAR     BYTE[80]            
COUNTER     VAR     BYTE                   
VOL         VAR     BYTE                   
SOLO        VAR     BIT

Thanks.

[Charles Linquis]

Bruce, could you please explain your comment to me? I would think that PBP knows what bank it is in, and keeps track of that - even in an interrupt handler. Is that not true?
And what constitutes "outside the interrupt handler"? Must all the handler code be placed between the INT entry point and the INT_RETURN?
I have to admit, I have violated your "rule" and it hasn't caused problems. Am I lucky?
Please explain.

[Michael Wakileh]

? toggle command is only good for port pins ?

[circuitpro]

Oh my gosh, you're right! I don't know why I thought that would work for a bit. That fixed it.

THANKS Michael.