Purpose: Return screen format
Call address: $FFED (hex) 65517 (decimal)
Communication registers: X, Y
Preparatory routines: None
Stack requirements: 2
Registers affected: X, Y
Description: This routine returns the format of the screen, e.g., 40 columns in X and 25 lines in Y. The routine can be used to determine what machine a program is running on. This function has been implemented on the Commodore 64 to help upward compatibility of your programs.
How to Use:
EXAMPLE:
JSR SCREEN STX MAXCOL STY MAXROW