Comment by qingcharles

The answer is "no time at all." I used Gemini Ultra earlier this year to see how well it would do with some really gnarly assembler. I asked it to write a whole flat-shaded 3D engine in 8086 assembler that would run in CGA on an original XT and it one-shotted it in a couple of minutes.

https://imgur.com/a/Dy5rUku