Detailed info on Basic USR command...
Posted: Sun Oct 15, 2006 8:10 pm
I've been looking for some detailed info regarding the Atari Basic USR command. What I need to know is how parameters are passed.
If I have a routine called with say:
U=USR(ADR(STRINGWITHML$),ADR(STRINGWITHDATA$),ADDRESS,LENGTH,X,Y)
How are they sent. I know that the you need to include a PLA at the start of the routine. What is first PLA pulling off the stack? The number of parameters? Now for my next PLA, will it be pulling the value for Y first, or the LSB of ADR(STRINGWITHML$)?
Any info would be appreciated.... Thanks
If I have a routine called with say:
U=USR(ADR(STRINGWITHML$),ADR(STRINGWITHDATA$),ADDRESS,LENGTH,X,Y)
How are they sent. I know that the you need to include a PLA at the start of the routine. What is first PLA pulling off the stack? The number of parameters? Now for my next PLA, will it be pulling the value for Y first, or the LSB of ADR(STRINGWITHML$)?
Any info would be appreciated.... Thanks