After having over 600 failing tests at one point, this does feel good.
Even better, most of the risc/interpreter tests where i didn't change anything came gree without changing the tests. ie we have binary compatibility.
Since Builtin generates risc, just like mom instructions, it was a design mistake to put builtin into risc in the first place. Now that borders are coming more into focus, it make much more sense to have the builtin in mom.
In fact the instructions should be moved out and a seperate invocation mechanism used , so functions can be parsed, not generated (wip)