SimHYMN

SimHYMN is an educational tool developed in Java, which simulates a simple CPU with 8 instructions and 32-byte memory. It can be used to learn how programs are executed by the CPU, which has three registers: IR (instruction register), PC (program counter) and AC (accumulator).

Simple interface and options

The interface is user-friendly, made from a colorful window that displays the CPU instructions, PC, IR and AC settings, along with the CPU speed and I/O data.
It's possible to adjust the CPU speed, modify the binary values of the instructions by clicking on digits to toggle 1 and 0, change the PC, IR and AC settings while keeping track of zero and positive flags, as well as execute the processor with one click.
Moreover, you can take a step forward or back, reset the CPU, insert or delete bytes from the binary memory address, clear the memory, open and save images, edit code using the assembler, view errors, assemble from file, increase the font size, as well as print the window.

No setup necessary, besides Java

The entire application's wrapped in a single executable .jar file that can be saved in a custom location on the disk or stored on a USB flash drive to seamlessly run SimHYMN on any computer with Java. It doesn't modify your system registry settings or create files on the disk without asking for permission.

Evaluation and conclusion

It didn't put a strain on the computer's performance in our tests, thanks to the fact that it needed a low amount of CPU and RAM to work properly. It remained stable throughout its runtime, without hanging, crashing or showing error dialogs.
All in all, SimHYMN delivers a simple environment for simulating an 8-instruction CPU with 32-byte memory. It's free for non-commercial use.