@Clubby73 Not necessary relative addressing. Slots use the same addr space (typical Z80, #0000 to #FFFF, but you choose what 16KB segments to use, typically #4000-#BFFF, RAM is usually mapped at #C000 when using a cartridge).

You can also compile in DOS mode, (a .COM binary starting at #0100 and the whole address space mapped to RAM).

But as I said before, this part can be a bit confusing so better focus yourself on finishing the core compiler for Z80 and revisit this topic in the future ;-)