41: What's the significance of the alpha mark (ᵀ) prefix on catalog 2 entries?

[Dave Britten]

(01-23-2020 10:01 PM)rprosperi Wrote:  

(01-23-2020 08:09 AM)hth Wrote:  ... COPY does not take it argument from Alpha, you are expected to press XEQ "COPY" [Alpha] name [Alpha].

This is all because COPY is part of the mainframe (HP-41 original firmware) and it does not contain any code to take a name from Alpha. Such routines were introduced in the Extended Functions module and the HP-IL module.

Thanks for the correction! I never noticed that Functions taking arguments from existing Alpha register all came in or after the XFM, and that all mainframe functions did this the 'old' way. Like many such behavioral things, it makes sense, once you see the pattern.

I wonder why the switch. It's not like a function couldn't take an indirect argument the way XEQ IND does if you needed a non-hard-coded argument. Was it to get around the 6-character register limit maybe? But for that matter, I wonder why the 41 doesn't support IND A.