byuu says:

Any usage of natural and integer cast to 64-bit math operations now.
Hopefully this will be the last of the major changes for a bit on
nall/primitives, at least until serious work begins on removing implicit
conversion to primitive types.

I also completed the initial TLCS900H core, sans SWI (kind of a ways off
from support interrupts.) I really shouldn't say completed, though. The
micro DMA unit is missing, interrupt priority handling is missing,
there's no debugger, and, of course, there's surely dozens of absolutely
critical CPU bugs that are going to be an absolute hellscape nightmare
to track down.

It was a damn shame, right up until the very last eight instructions,
[CP|LD][I|D](R), the instruction encoding was consistent. Of course,
there could be other inconsistencies that I missed. In fact, that's
somewhat likely ... sigh.