Base conversion for DM41X

[Jeff_Birt]

(10-22-2023 04:16 PM)Valentin Albillo Wrote:  It would probably be good for you and save much time if you would go on and read the Owner's Handbook, which explains everything in a simple yet complete manner and in fact it's quite an enjoyable, productive read.

The information you're asking about local alpha labels is perfectly explained in pages 188 and 189, so do yourself a favor and read it before asking here.

V.

I have read through all of Part I of the HP-41CX Owner's manual and am using Part II as a reference. Forgive me for not committing 400+ pages of technical documentation to memory in two weeks. If part of the purpose of a forum is not to ask questions than what is the point? Scolding someone who is new to a particular machine for asking a question is not particularly friendly nor constructive.

Looking at volume on of the HP-41CX User's manual this is found on page 88. From reading this I could not guess as this auto-assignment of A-F scheme.

"Local labels are not listed in catalog 1 and cannot be assigned to the User keyboard. This is because local labels are for strictly “local” use; they can only be used within the context of a single program."


Looking at the HP-41CX User's manual volume 2 on page 300 reveals this:

"Local Alpha labels require two bytes of program memory and can be used for branching any distance within a program. They are designed for manual execution: when the User keyboard is active, a local Alpha label is automatically assigned to each key on the top two rows (as described in “The Top Two Rows” in section 9). You can then use these keys to execute the corresponding local Alpha labels in the current program."

Then if you look up Section 9 it goes into more detail. To summarize while the HP-41C manual you linked to does mention this auto-assignment up front the HP141CX manual does not. In fact, the first mention of local labels in volume 1 would suggest the opposite to the new reader. One has to read three separate sections to get the full picture of this one feature.

To answer my own question about how the machine knows what program these top two rows of keys might be assigned to its scope is the 'current program'. If one has not executed the base conversion program, you would need to GTO to its global label to bring it into scope first. This is an interesting functionality and could be very handy for repetitive operations.