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https://github.com/leonmavr/HIP35

HP-35 RPN calculator emulator in C++17 with a terminal user interface
https://github.com/leonmavr/HIP35
calculator cpp emulator hp-35 ncurses rpn
Last synced: about 2 months ago
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HP-35 RPN calculator emulator in C++17 with a terminal user interface
Host: GitHub
URL: https://github.com/leonmavr/HIP35
Owner: leonmavr
License: mit
Created: 2023-09-03T10:43:50.000Z (10 months ago)
Default Branch: master
Last Pushed: 2024-03-31T18:40:21.000Z (3 months ago)
Last Synced: 2024-03-31T19:30:20.004Z (3 months ago)
Topics: calculator, cpp, emulator, hp-35, ncurses, rpn
Language: C++
Homepage:
Size: 64 MB
Stars: 4
Watchers: 1
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists

cli-apps - HIP35 - HP-35 RPN calculator emulator in C++17 with a terminal user interface. (<a name="calc"></a>Calculators)
awesome-cli-apps - HIP35 - HP-35 RPN calculator emulator in C++17 with a terminal user interface. (<a name="calc"></a>Calculators)
README

        ```

 .----------------. .----------------. .----------------. .----------------. .----------------. .----------------. 

| .--------------. | .--------------. | .--------------. | .--------------. | .--------------. | .--------------. |

| |  ____  ____  | | |     _____    | | |   ______     | | |              | | |    ______    | | |   _______    | |

| | |_   ||   _| | | |    |_   _|   | | |  |_   __ \   | | |              | | |   / ____ `.  | | |  |  _____|   | |

| |   | |__| |   | | |      | |     | | |    | |__) |  | | |    ______    | | |   `'  __) |  | | |  | |____     | |

| |   |  __  |   | | |      | |     | | |    |  ___/   | | |   |______|   | | |   _  |__ '.  | | |  '_.____''.  | |

| |  _| |  | |_  | | |     _| |_    | | |   _| |_      | | |              | | |  | \____) |  | | |  | \____) |  | |

| | |____||____| | | |    |_____|   | | |  |_____|     | | |              | | |   \______.'  | | |   \______.'  | |

| |              | | |              | | |              | | |              | | |              | | |              | |

| '--------------' | '--------------' | '--------------' | '--------------' | '--------------' | '--------------' |

 '----------------' '----------------' '----------------' '----------------' '----------------' '----------------'

```

_{(ASCII art by [patorjk.com](https://patorjk.com/software/taag))}

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)

[![C/C++ CI build & test](https://github.com/leonmavr/HIP35/actions/workflows/c-cpp.yml/badge.svg)](https://github.com/leonmavr/HIP35/actions/workflows/c-cpp.yml)

## 1. Introduction

### What's this project?

HIP-35 is a calculator for hipsters. It emulates the RPN (reverse

Polish notation) mode of HP-35 from 1972. It runs a terminal UI

built with ncurses that displays the current result on a display.

### ⚫ Why RPN?

Because it genally involves less keystrokes and it's faster than

algebraic notation calculations.  

How? RPN makes it very easy to compute long expressions containing

lots of brackets [[1]](#ref-1). When using it, you don't need

to think how terms are grouped anymore.

### ⚫ The memory

HP-35 had a stack-based memory of 4 registers `X`, `Y`, `Z`, `T`

with `X` being the bottom (entry). That stack shifts (lifts or

drops) automatically as calculations are performed. There are

also 10 general registers labelled `A` to `J` that store values,

acting as buffers.

| HP-35 | HIP-35 |

|---------|---------|

|  |  |

## 2. Usage

### ⚫ Dependencies

CMake is required to build the project and ncurses for the frontend.

Also you need to make sure your compuler supports **C++17** or higher.

Install both packages by:

| Arch-based                     | Debian-based                                       |

|--------------------------------|----------------------------------------------------|

| `sudo pacman -S cmake ncurses` | `sudo apt install cmake libncurses5 libncursesw5`  |

### ⚫ Compilation

The build system is based on CMake. To build the project run:

```

cmake . -Bbuild

cd build

make -j

```

or alternatively just execute the `build.sh` script:

```

./build.sh

```

The demo executable that runs the UI will be generated at

```

./build/demo/demo

```

That's it, have fun doing RPN calculations!

A unit test executable is also generated at

`./build/test/testhip35`.

### ⚫ The keys

Most keys are self-explanatory. However, some are less straightforward.

| key   | description             | syntax    | before            | argument | after             |

|-------|-------------------------|-----------|-------------------|----------|-------------------|

| CHS   | change sign of X        | `CHS`     | 4                 |          | -4                |

| ENTER | duplicate X to Y        | `ENTER`   | `T,Z,Y,X=1,2,3,4` |          | `T,Z,Y,X=2,3,4,4` |

| LASTX | last X before operation | `LASTX`   | `4 E 20 +` (X=24) |          | `X=20`            |

| RDN   | rotate stack down       | `RDN`     | `T,Z,Y,X=1,2,3,4` |          | `T,Z,Y,X=4,3,2,1` |

| STO   | store to A-J e.g. A = X | `STO a-j` | `X=3.14, A=0`     | a        | `X=3.14, A=3.14`  |

| RCL   | recall to X e.g. X = A  | `RCL a-j` | `X=0, F=2.71`     | f        | `X=2.71, F=2.71`  |

| EEX   | exponentiation of X     | `EEX N`   | 7                 | 3        | 7000              |

| CLX   | clear register X        | `CLX`     | 12345             |          | 0                 |

| CLR   | clear entire stack      | `CLR`     | `T,Z,Y,X=1,2,3,4` |          | `T,Z,Y,X=0,0,0,0` |

| q     | quit application        | `q`       |                   |          |                   |

Enter (``) needs to be pressed to separate two successive

numbers. When running the UI, press `q` to quit. `` is 

not captured so `q` is the only way to quit. You can read more 

at the [HP35 manual](https://literature.hpcalc.org/community/hp35-om-en-reddot.pdf)

[[4]](#ref-4).

### ⚫ Project directory structure and source code

Implementations are found at `lib/src` and header files at `lib/inc`. The demo application is at `demo/main.cpp` and unit tests are found at `test/test.cpp`. 

You can create an instance of the Hip35 class and run it either via 

the UI or without it (given a string) as follows:

```

#include "hip35.h"

//...

auto hp = std::make_unique(key::keypad);

// using the UI

hp->RunUI();

// or without it

auto result = hp->EvalString("430 ENTER 80 - 1.2 *");

```

## 3. Demo

Second order equation by using storage/recall:

https://github.com/leonmavr/HIP35/assets/13514096/911e7cce-2db0-4705-92fd-c3dfa6142de6

The fraction `sqrt(2 + (sin(25) + pi/2)^2)/3`:

https://github.com/leonmavr/HIP35/assets/13514096/ee05b992-8901-4ffe-9649-71dfb9cda71c

## 4. Basic theory

### ⚫ What is RPN?

RPN allows a stack-based evaluation of numerical expressions,

eliminating the need of brackets. There are two main ideas behind

RPN:

1. operands (numbers) are pushed in a stack

2. it follows the postfix notation, i.e. each operator follows one

or two operands preceeding it

Physical calculators need a way to separate successive numbers,

accomplished with the enter (E) key.

For example:

```

+------------+---------------+-------------------+-----------------------------------------------+

| Algebrainc | RPN           | Physical          | Stack contents                                |

| expression | equivalent    | calculator        |                                               |

+------------+---------------+-------------------+-----------------------------------------------+

| 1 + 2      | 1 2 +         | 1 E 2 +           | [1], [1,1], [1,2], [3]                        |

+------------+---------------+-------------------+-----------------------------------------------+

| 1 + 2 - 3  | 1 2 3 + - or: | 1 E 2 E 3 + -     | ...[1,2], [1,2,2], [1,2,3], [1,-1], [0]       |

|            | 1 2 + 3 -     | 1 E 2 + 3 -       | ...[1,2], [3], [3,-3], [0]                    |

+------------+---------------+-------------------+-----------------------------------------------+

| (1+2)(3+4) | 1 2 + 3 4 + * | 1 E 2 + 3 E 4 + * | ...[1,2], [3], [3,3], [3,3,4], [3,7], [21]    |

+------------+---------------+-------------------+-----------------------------------------------+

| 13*sin(37) | 13 37 SIN *   | 13 E 37 SIN *     | [13], [13,13], [13,37] [13,s(37)], [13*s(37)] |

+------------+---------------+-------------------+-----------------------------------------------+

```

You can practise more with RPN by using the script `docs/rpn.py`

which evaluates RPN expressions from a string. Numbers are

separated by space in this script so you don't need to press enter.

### ⚫ HIP-35 additional features

HIP-35 includes some minor additions compared to HP-35:

* The display now has two rows, displaying the X and Y registers

instead of just X.

* There is space on the right to display the 10 general registers.

Back in the day users had to write down which register stores

what.

* User can also enter negative numbers using the `~` as the unary

minus. HP35 only supposed the `CHS` (change sign) operation for

that.

* There is no `ARC` key. `ARC` key had to pressed to enable the

`SIN, COS, TAN` keys to compute `ASIN, ACOS, ATAN`. The latter

keys are directly implemented in HIP-35.

* The number format on the display is automatically adjusted based

on the range the number is in.

* The `LASTX` key from HP-35s is ported as it makes certain 

calculations much faster.

You can read more at the [wiki](https://en.wikipedia.org/wiki/HP-35)

page, at [HP museum](https://www.hpmuseum.org/hp35.htm) or at the

[HP-35s manual](http://h10032.www1.hp.com/ctg/Manual/c01579350),

which is its successor.

### ⚫ Cool trivia

* HP35 was the first ever scientific pocket calculator. It was

  released in 1972. Before that, the only practical portable

  devices for performing trigonometric and exponential functions

  were slide rules [[2]](#ref-2)

* The co-founder of HP himself, Bill Hewlett, challenged his

coworkers to create it as a "shirt-pocket sized HP-9100“ (HP-9100

was a scientific computer from the 60s).

* HP-35 calculators, were used by NASA's Skylab crew from 1973 to

1974 [[3]](#ref-3). It's rumored to be the first

calculator to ever fly into space. It helped the crew write

programs that perform calculations related to the spacecraft's

orbit around the moon (Lunar Orbital Rendezvous or LOR).

* It was able to perform calculations both in algebraic a RPN mode.

## 5. Future ideas

- [ ] Paste text into display

- [ ] In headless mode (parsing a string), throw an error instead of

      continuing when a token is unknown.

- [ ] (ambitious) write a compiler for the HP35/HP35s programming

	  language and be able to write routines by pressing a key.

## 6. Donations

I'm looking to raise about 150-200 euros to buy a second hand

HP-35 calculator so I can compare my emulator against it. Feel

free to donate any amount to:

 [leonmavr](https://paypal.me/leonmavr)  

 ``36e6wNQ64dGXGDKQMn8LzWC3zSon1SvVJQ``

## References

[1] [Dr Marshall Leach Jr's page](https://leachlegacy.ece.gatech.edu/revpol/)  

[2] [Interview with David Cochran](https://killerinnovations.com/interview-with-david-cochran-on-creating-the-hp35-calculator/)  

[3] [History of Space Shuttle Rendezvous, Oct 2011](https://core.ac.uk/download/pdf/10564548.pdf)  

[4] [HP35 manual](https://literature.hpcalc.org/community/hp35-om-en-reddot.pdf)