While this is an interesting book in its genre, I prefer to read actual MMIX code in The MMIX Supplement by Martin Ruckert[0]. The relation between the two books resembles that between, say, Manual of Surgery and Frankenstein, or Teach Yourself Romanian and Dracula.
Can anyone comment on whether MMIX is still used for teaching? I figure it makes more sense to just teach, say, AArch64, these days. I'm not convinced that enough is gained by using an 'idealised' instruction-set, to balance out that it's not seen in the real world.
We used it for our assembly course in 2013. A new professor joined the department the year after I took the class and he taught something else, so from then it depended who was teaching the course that year. It was a small teaching university (we had 5 CS grads my year) that was part of the math department (it has since moved to the school of engineering).
I never touched any form of assembly after that course so I don’t think it made a big difference one way or the other. My memory is hazy, but I think there might have been a personal connection between my professor and Knuth - they are roughly from the same generation.
[0] https://www.amazon.com/MMIX-Supplement-Computer-Programming-...