HP 41 - branching to local label and return stack - FINAL RESULTS AND PROGRAMS

[Artur - Brasil]

(05-20-2019 03:00 PM)Craig Bladow Wrote:  I believe 'prompt' is looking for the user to enter a number.

This works (i.e. returns) where the user enters a number from 1-4 corresponding to the menu item.

SFTMEN program:
01 - LBL "SFTMEN"
02 - PROMPT
03 - STO 42
06 - RTN

Actually, this prompt expects:
A number (data) and corresponding key - will get the register number to store this data; next will store data in it; so, will turn on a control flag and will return to menu;
Just the corresponding Key pressed - will get the register number that holds the data and will display (PSE) it; so, will turn on a control flag and will return to menu;
R/S - if the user informed data or get the data diplayed before, the control flag will be ON and this last variable input/viewed saved. So, pressing R/S will solve for this last variable.
R/S without previous data input or data viewing - an error (BEEP) and returns to menu.

It mimics the HP-12C for solvind financial data, but with some increments...

Quote:Also in USER mode the top two rows of keys will directly execute routines if they have the LBL A-J in the current program.
That would look like:
MAIN:
01 - LBL "AUTO"
02 - "BA:POT:IMP:CUR:"
03 - AVIEW
04 - STOP
05 - LBL A
.......

This is what I was expecting to happen and 41 actually does it, but with a big mistake: it kills the return stack, so, I can't go back to the main program!
I was reading about Synthetic Programming and return stack is kept in registers a and b. If I could save these registers before the PROMPT and restore them back in the labels A, B, C ... this would be one (uggly) solution for this problem. But such routine in Synthetic Program is for big guys...