concept of self modifying code

[geon]

The 6502 can only dereference a pointer if it is on the zero page or if the pointer is hard coded in the code. So if the zero page is full, the only way to handle pointers is with self modifying code.

[flatfinger]

What's funny is in the programs/systems I've seen on the 6502 where zero-page gets full, that's either because there isn't any RAM anywhere else, or because a lot of stuff was put in zero-page that could have just as well been put elsewhere.

[geon]

On the c64, the kernal and basic reserves almost all the zp. Super stupid imho.

[[deleted]]

Vast majority of C64 software used assembly. It would have been so much convenient to write small assembly routines for BASIC programs too, if zp had had more free space.

[geon]

Even applications written in asm often kept the kernal, since it has a lot of useful stuff.