Free42 NSTK ENTER behavior

[toml_12953]

(10-17-2021 03:25 PM)BruceH Wrote:  

(10-17-2021 09:11 AM)ijabbott Wrote:  That is impossible with the 4STK model because losing numbers off the top of the stack is part of the normal operation.

Hans Klever gave an excellent presentation at Allschwil 2018 showing how overflow on a 4-stack machine can be caught.

To back it up, he implemented his ideas on a modified HP-35 emulator which can be found here.

Nice! The function of the LED seems backward to me, however. I'd like to see a light when an error condition exists and not when everything is normal. I'd reverse the NO to read Overflow and illuminate it when the stack overflowed.