How to launch a C64 program from a C128 in 128 mode:
100 REM MODE SELECT PROGRAM
120 REM VERSION 1.0
130 REM VARIABLES
140 M = ABS (PEEK(65533)=255)Location 65533 will return a unique value depending on the mode / machine which is running.
- 252 will be returned if in 64 mode
- 255 will be returned if in 128 mode
Using the ABS function allows us to make the variable M equal to either 0 or 1, based on whether the statements enclosed in parenthesis after the ABS are true or not. Thus, if location 65533 holds a value of 255, M becomes 1. If some other value is found, M becomes 0.
150 IF M = 1 THEN 200
160 IF M = 0 THEN 300
170 PRINT "MACHINE TYPE UNKNOWN"
180 END
200 PRINT "YOU ARE USING A COMMODORE 128"
210 END
300 PRINT "YOU ARE USING A COMMODORE 64"
310 END