Each instruction node uses a bit pattern that represents its encoding shape at that level. It has two main properties:
width, which is the width of the encodeset in bits.values, which is a list of fields (representing fields or bits) defined at the current level.If part of an Encodeset is unspecified in both the current instruction node
and all of its parent nodes, that part is considered to be an "any-bit"
('1' or '0', usually denoted as 'x').
If part of the local Encodeset is unspecified but that same part has a value specified in a parent node, the value of that part is inherited in the local Encodeset.
For more information about the types of field, see the following: