We can define functions to factor out a repeated piece of logic that we later reuse multiple times in a design. For example, we can wrap up our earlier example of a simple combinational logic block as follows:
def clb(a: UInt, b: UInt, c: UInt, d: UInt): UInt =
(a & b) | (~c & d)where clb is the function which takes a, b,
c, d as arguments and returns a wire to the output of a
boolean circuit. The def keyword is part of Scala and
introduces a function definition, with each argument followed by a colon then its type,
and the function return type given after the colon following the
argument list. The equals (=})sign separates the function argument list from the function
definition.
We can then use the block in another circuit as follows:
val out = clb(a,b,c,d)We will later describe many powerful ways to use functions to construct hardware using Scala's functional programming support.
[Prev (Builtin Operators)](Builtin Operators) [Next (Bundles and Vecs)](Bundles and Vecs)