// args[i] == 0 marks the end of the argument list.
type instFormat struct {
	mask     uint32
	value    uint32
	priority int8
	op       Op
	opBits   uint64
	args     instArgs
}

type instArgs [4]instArg

var (
	errMode    = fmt.Errorf("unsupported execution mode")
	errShort   = fmt.Errorf("truncated instruction")
	errUnknown = fmt.Errorf("unknown instruction")
)

var decoderCover []bool