## A Calculator – Completed!

It has been a while since I wrote the last post on this project. In the meantime, I could dedicate all my limited free time to work on the implementation. It took a long time, but I did make significant progress. The calculator is pretty much completed.

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## A Calculator (4): The Framework

For as long as I remember, I had played with LEGOs. Those simple blocks would transform into complex objects whose final shapes only existed in the supple thoughts of creative imagination. The kind of LEGO blocks we had while growing up were simple: 2×4, 2×2, 1×8. Anything unusual was rare and precious.

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## A Calculator (3): Practical Numerical Methods

In the last post, we verified and quantified the precision of the basic four functions (addition, subtraction, multiplication, and division). Now, we can use them as a stepping stone for more complex functions. We can assume they will be available, so our experimentation could simply use built-in C++ functions.

In this article, the third in a series, we will continue with the proof-of-concept, or pathfinding, research.

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## A Calculator (2): Basic Four Functions

This is the second article in a series on making our calculator. This article is about prototyping and the verification of fundamental algorithms.

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## A Calculator

The idea for this project came about during a week of freezing winter arctic events here in Austin, Texas, with a failed power grid (as well as the Texas government), while keeping close to a gas fireplace, the only source of heat and light, for a couple of days. With a weak internet over a phone data line, I could only do some preliminary searches and mainly work out various details on a writing pad, growing feeling that the project may be personally exciting and practically doable.

It took a long time, but this FPGA Calculator is now finished and I am really happy with how well it turned out.

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## Flight Sim Remote Panel / 2

Flight Sim Remote Panel (or its alias name, “XPlaneRemote”) is an application that shows the basic general aviation instrument set on your Android phone or tablet. It is not a flight simulator – a copy of X-Plane 11 should be running on your desktop or a laptop – this application connects to it from an Android device and displays the flight instruments, hence the “remote panel” in its name.

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## PlayZX

PlayZX is an Android application that lets you select from thousands of Sinclair ZX Spectrum games and play them through the headphone jack to load them onto your Speccy. You can also select your local (on the device) files, convert them to sound files, and then play them. This way, you can load games for the ZX Spectrum micro and a few other retro computers with a compatible audio jack.

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## ZX Spectrum ROM mods

In this blog, I will show you how to interface an Atari-style joystick to the Altera DE1 FPGA board running a Spectrum implementation, how to change the ROM to enable you to input some game-cheat pokes, and a few games I eventually completed using this setup.

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