add error message on invalid register
remove assembler from future work
remove reference to incorrect J type encoding
It turns out I was actually using the same encoding as RARs after all.
Also, as described in the relevant issue on the RARs repo, it was the
correct style all along.
get fibo test case working
implement label resolution
got J types working, I think?
Either I am very confused, or RARS has at least one problem with it's J
type encoding, which means that riscv.awk disagrees with it (which also
breaks the relevant test cases). I have reported the issue upstream
assemble I, R, and shift types
start sketching out the assembler
add conditional branch instructions