hypothetical: more return stack levels on 11C, 15C, 16C

[brouhaha]

How often do people run into the limit on return stack levels on the HP-11C, HP-15C, or HP-16C?

Does anyone have an actual use case where more return stack levels (perhaps double the current number) on those calculators would be particularly useful? Possibly in conjunction with having more program steps available, and possibly more labels?

For a while now, I've been hacking on the 15C and 16C microcode, lately mostly focusing on 16C improvements. I've already got the 16C memory increased from 203 bytes to 1547 bytes (combined program and registers, with up to 999 program steps), and added trig, inverse trig, logs, and exponentials (in float mode only).

Increasing the return stack size wouldn't be too difficult, but increasing it substantially (like Free42) would slow down GSB and RTN, so I'd most likely only add a small number of extra levels. This means that it wouldn't be too useful for recursion, but it would be useful for cases where the normal calculator is a little short on subroutine levels.

On the other hand, it's remotely possible that some programs exist that actually depend on the behavior with the limited stack.

I've considered this for the 41C/CV/CX also, but any significant changes to the 41 microcode and memory utilization run the risk of breaking synthetic programs that directly muck around with the status registers, and might also interfere with some microcoded ROM module functions. For exmaple, I'd have to test it with SOLVE and INTEG in the Advantage Pac.