Stack Overflow Sensing (or: make your own Red Dot!)

[hansklav]

Inspired by the proposal of John A. Ball in his book ‘Algorithms for RPN Calculators’, as a proof of concept I implemented a stack overflow sensing (SOS) scheme using Neil Fraser's JavaScript HP-35 simulator.

In the process I made my own ‘Red Dot’ HP-35 calculator ;-)

Have a look here and see for yourself if HP missed a chance to build SOS into its very first pocket calculator (and, incidentally, into all its subsequent classical RPN models).

Hans

P.S.: I discovered a small inaccuracy in the functioning of the π-key of the original HP-35 simulator and corrected it in the HP-35 SOS.

[PANAMATIK]

(04-16-2015 11:08 PM)hansklav Wrote:  Inspired by the proposal of John A. Ball in his book ‘Algorithms for RPN Calculators’, as a proof of concept I implemented a stack overflow sensing (SOS) scheme using Neil Fraser's JavaScript HP-35 simulator.

In the process I made my own ‘Red Dot’ HP-35 calculator ;-)

Have a look here and see for yourself if HP missed a chance to build SOS into its very first pocket calculator (and, incidentally, into all its subsequent classical RPN models).

Hans

P.S.: I discovered a small inaccuracy in the functioning of the π-key of the original HP-35 simulator and corrected it in the HP-35 SOS.

This is interesting. As I understood you made patches of the original HP-35 firmware. Do you think it could be possible to make further changes like adding new functions, making the HP-35 a programmable calculator, or write a compiler for ACT firmware?

Bernhard

[Thomas Klemm]

(04-18-2015 10:25 AM)PANAMATIK Wrote:  As I understood you made patches of the original HP-35 firmware.

From Neil Fraser's HP-35 RPN Calculator

Quote:Since they did not have a simulator for the HP-35, I wrote one in JavaScript for them. The result is a very faithful simulation with the exception of some rounding errors.

Cheers
Thomas

[PANAMATIK]

Thanks Thomas for clarifying this.

As I understand now, this HP-35 simulator does not emulate the original HP-35 firmware.

Bernhard

[hansklav]

(04-18-2015 03:55 PM)PANAMATIK Wrote:  As I understand now, this HP-35 simulator does not emulate the original HP-35 firmware.

You’re quite right: Neil Fraser’s JavaScript HP-35 simulator doesn’t emulate the HP-35 firmware but it does emulate its external behaviour. My modification of it (the ‘HP-35 SOS’) adds one feature, Stack Overflow Sensing (SOS) to show how this could work out for the user of a classical RPN calculator.

You can download the source code (or simply study it from within your webbrowser); I documented all the added/modified lines.

Hans