and epilogues. mcgg now exports some useful data as headers. Start factoring
out some of the architecture-specific bits into an architecture-specific file.
turned into generic ones (as they'll be useful everywhere). Node arguments for
predicates require the '%' prefix for consistency. Hex numbers are permitted.
instructions can be turned on and off based on their parameters. New lexer
using a lexer. Now quite a lot of the way towards being a real instruction
selector.
