[mek6800d2]

@kens beat me to it-I too was going to suggest Ken Shirriff's "Reversing Sinclair's amazing 1974 calculator hack". The page has a Sinclair Scientific emulator that displays the running, underlying calculator chip instructions.

I bought the Sinclair Scientific in 1974 for a physics lab class in college. It was much less expensive than the TI and HP scientific calculators of the time, but it was painful to use in the lab class. I subsequently changed majors, so I only had to bear with it that first year, but, all these years later, I'm still in awe of what Sinclair achieved with it though!