(41) program/function label/name ROM pages "path"

[rprosperi]

FOCAL programs don't store a ROM program/function's name, it stores the analogous XROM XX,NN for that program/function in the ROM.

User programs (CAT-1 and I believe CAT-2) are searched before CAT-3, so a user program can essentially 'take over' a built-in function (e.g. if you make a program with global label "MOD", later when you XEQ "MOD", your function is called, not the OS function).

That aside, I believe the system scans pages 4-F in increasing order looking for a global label to match if executed manually, or when entering a program.

But once XROM XX,NN is encoded in a program for some function, it will run the first one matching that value that it finds as it searches, even if it's not the same ROM that was present (or possibly in a lower age) when the program was stored.

This is why HP labeled many of their later ROMs with "X" - they all shared the same XROM "XX" of 19. The label X was to remind you to not have multiple inserted at the same time, and generally to be aware of the common XROM usage.

I can't comment on MCODE, though I'd guess it follows the same rules; otherwise I imagine things would get messy...