Using the screen link table for ZP addresses

[IsaacKuo]

What sort of "bad stuff" might happen if you use locations 217-240 -- the screen line link table? Am I correct in assuming they will neither be accessed or overwritten if you avoid all of the following?

1) Print RETURN, <shift>-RETURN, INSERT, CLR HOME
2) Print something into the right column of the screen
3) Print DOWN from bottom row

If this is correct, then the screen line link table can be a huge expanse of zero page suitable for storing lots of variables and/or a decent table. You could use and then fill it with 158 after you're done.

[nbla000]

There is no problems if you "Poke" chars on the screen memory but you cannot use standard print kernel routine.

[Mike]

As Nicola said, KERNAL I/O to screen via CHROUT and CHRIN/BASIN should be avoided in that case.

You could use and then fill it with 158 after you're done.

The screen link table contains the high byte of the screen line, +0 if it is linked, +128 if it is not linked. Obviously the default values are going to change when screen memory is moved, for example when memory expansions of +8K or more are in use.