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The HP-41 calculators can be programmed with microcode, aka MCODE. This is how their normal instructions are implemented. The emulator even has an MCODE console where  you can step though its instructions. On the physical machine running your own MCODE requires making ROMs (or something that pretends to be a ROM…). I am not familiar … Continue reading »

If you have the PPC ROM synthesizing instructions is much easier, and you don’t have to “jailbreak” the calculator. I believe assemblers/compilers that also work with the emulator makes this even easier. I have actually not tested this, but I do think they support synthetic instructions.

One of the most fun things to do on an HP-41 is to start utilizing instructions you cannot key in but that still are actually functioning codes. Slicing bytecodes together to make these instructions is called “Synthetic Programming”, as they will have to be “synthesized” in some more or less artificial manner than using the … Continue reading »

There is actually an online emulator for my very first programmable calculator, the TI-51 III, aka TI-55. Just start pushing buttons! Even the on/off switch works.

The TI screenshots below were downloaded from the “TI-SmartView CE-T Emulator Software”, as getting screenshots from the calculator itself does not work regardless of connection method. The HP screenshots were taken in the “V41” virtual HP-41. Programs were also downloaded from the emulator and decompiled using “HP41UC“, an ancient 16-bit HP-41 compiler/decompiler that today must … Continue reading »

It was much more fun to program this on my old HP calculator (not necessarily an optimal solution, but I wrote this around 40 years ago, my very first version…): LBL “HANOI” “N?” PROMPT STO 01 “A” ASTO 02 “B” ASTO 03 “C” ASTO 04 10 STO 00 XEQ “INFIX” STOP LBL “INFIX” 1 RCL … Continue reading »

The Tower of Hanoi is something I “have to” do on any calculator I encounter, but using Python feels almost like cheating, it is just too easy. Unfortunately there is little else of interest for this task on this calculator. def hanoi(n,a,b,c): if n==1: print(a,” >> “,b) else: hanoi(n-1,a,c,b) hanoi(1,a,b,c) hanoi(n-1,c,b,a) hanoi(3,1,2,3) To fit it … Continue reading »

Here you can see the program running: The numbers can of course be complex, so let us try a different input:

Believe it or not, even with their strict limitations, the fairly simplistic functions from the last post are sufficient building blocks to demonstrate a simple quantum circuit. Now we just have to declare the necessary quantum gates and initialize the three input qubits and we are ready to actually “build” the circuit. This is the … Continue reading »

We will need a few functions to do necessary mathematical operations on qubits (or more specifically on the state vector or probability vector of a quantum system). Note that I follow what I believe is the most common numbering of inputs with qubit 0 being the first input from above in the circuit and the … Continue reading »