HP-41 - Memory modules

[grsbanks]

On a 41C you have to use EMDIR to get a listing of the files in extended memory and the number of registers of X-Mem free is returned to X.

You also need the X-Func module on a 41C or CV to be able to use an X-Mem module. The CX has the X-Func module baked into its ROM so you don't need that module.

The X-Func module provides 126 registers of X-Mem of which 124 are usable. Each X-Mem module provides a further 240 registers of which 238 are usable. So, after running EMDIR, X should be left with 124, 362 or 600 depending on the number of X-Mem modules installed.

If you plug two X-Mem modules into the 41C, make sure they are not one underneath the other. Either have them both in the same row or organized diagonally.