Cassie Jones [Sat, 11 Jan 2020 11:57:34 +0000 (06:57 -0500)]
Add parser and encoder tests, fix a parser bug
We test the parser by parsing an instruction, and then encoding it back
to binary, printed nicely. The test cases are generated by looking at
the spec table.
The parser was incorrectly parsing LD2U as ST2U. Fixed.