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.
Using the screen link table for ZP addresses
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As Nicola said, KERNAL I/O to screen via CHROUT and CHRIN/BASIN should be avoided in that case.
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.IsaacKuo wrote:You could use and then fill it with 158 after you're done.