Keyboard Interface

[psanders]

I have this question to answer and am not a programmer, can anyone please help, I would be very grateful.

"below is a low level subroutine that reads a character from the keyboard interface. The subroutine returns with the ASCII code for the key presses in the accumulator (A register) if new data is available, or zero if no new data is available. Write down the missing items marked 1 - 4

load direct A 8001
AND immediate A 1
Jump relative if zero A 2
3
4
store direct A 0000
return

 

[AmkG]

And what is the processor supposed to be?

This looks like pseudo-code, better read your manual; we can't answer it unless we find out how your processor or computer uses addresses and how they do I/O.

"Information has a tendency to be free. Which means someone will always tell you something you don't want to know."