Nah, I'm pretty sure there's exactly as much (assembly) as I'd think because I spent some time prodding it before writing the question in the first place.
You likely understand what it does much better than me, but I'm under no illusion that there's a lot of this code, nor indeed that it's problematic to use this code.
However I'm not at all convinced that porting "hand written assembler to higher level generators" is a good strategy for this specific code. It serves to launder the creativity, so that maybe some day one lawyer can convince another lawyer that A and B are distinct works despite every actual process along the convoluted path from A to B being mechanical... but it doesn't seem like it gets us closer to having a sustainable alternative.
And that's what I actually am interested in here, I think we want a Special Purpose language focused on emitting guaranteed constant time machine code for an algorithm. So that actually gets to the same Readability and Correctness goals you state, but rather than hoping to get away with writing Go (or any GP language) we accept that it's never going to make sense for a General Purpose language to prioritise this. IMO We're more or less guaranteeing one day we accidentally ship an Oracle.