PicoBlaze Simulator in JavaScript

[FlatAssembler]

I have tried to implement a terminal emulator for PicoBlaze inside my simulator. However, what I have made behaves rather unrealistically. Namely, on real PicoBlaze, you can type the data into the terminal while the program is running. In my PicoBlaze simulator, you need to type it before the program starts running. Right now, JavaScript blocks (disables) input into the terminal while there is a program running on the simulated PicoBlaze. If you circumvent that (by typing into a terminal while the program is paused), the simulator falls into an infinite loop. Any idea how to implement a remotely realistic terminal emulator in JavaScript? I have asked this question on Reddit as well, but so far got no response: https://www.reddit.com/r/learnjavascript...&context=3