A square-root approximation method that would halt on $\sqrt{378}$

Question

Back in the early $'90$s, I used to program in a (now obsolete) scripting language called LOGO.

Now, one peculiar glitch that I encountered at the time, was the interpreter halting on $\sqrt{378}$.

I clearly recall not being able to reproduce it with any value of than that specific one.

Ctrl/Break would terminate the operation, so that rules out HW-architecture issues.

My guess is that the approximation method has reached some sort of infinite loop.

So I've been wondering if it's possible to trace back on this method.

I am almost certain that I will not get an answer here, but I decided to give it a shot anyway:

• What square-root approximation methods are typically used?
• Is there a possible explanation for failing to approximate specific values?

Thanks

Answer 1

This is not an answer:

Welcome to Berkeley Logo version 5.5
? sqrt 378
You don't say what to do with 19.4422220952236