Bits defines the class of types that can be converted to bit vectors and back. Only types in the Bits class are synthesizable and can be stored in a state element, such as a Register or a FIFO.
At the lowest level, synthesizable objects can be considered as a wire or wires having some fixed width and interpretation. These correspond to Verilog wire and reg, and additionally have tighter semantics surrounding their use.
The Bit types are:
These Bit types can be combined into other types through the use of user defined structures or by using the many pre-defined types in the Bluespec FoundationIP Library.
Bluespec provides Data Type Conversion Functions for converting between types, or you can write your own functions.