Enum

Enum(UInt(), 3) creates a list of UInt literals with values 0, 1, 2.

Its usage includes the contruction of states when the Finite State Machine is constructed, as follows:

val sNone :: sOne1 :: sTwo1s :: Nil = Enum(UInt(), 3)

where the left hand side is a destructuring expression that binds successive elements from a list creating one binding for each and the final Nil matches the Nil at the end of the list.

Nil is required as the operators ending with colon, i.e. methods with names ending in a colon are executed on the right operand.

Example usage in Rocket Chip

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[1] https://groups.google.com/forum/#!topic/chisel-users/mDSV1ML-u9c [2] https://github.com/freechipsproject/chisel3/blob/70ca35b9d7b3884e5f701d49bc5286f89701fd14/src/test/scala/cookbook/FSM.scala