This example defines a component with inputs a
and b
, and a result
output.
At any time, result
will be the sum of a
and b
(combinatorial).
This sum is manualy done by a carry adder logic.
class CarryAdder(size : Int) extends Component{
val io = new Bundle{
val a = in UInt(size bits)
val b = in UInt(size bits)
val result = out UInt(size bits) //result = a + b
}
var c = False //Carry, like a VHDL variable
for (i <- 0 until size) {
//Create some intermediate value in the loop scope.
val a = io.a(i)
val b = io.b(i)
//The carry adder's asynchronous logic
io.result(i) := a ^ b ^ c
c \= (a & b) | (a & c) | (b & c); //variable assignment
}
}
object CarryAdderProject {
def main(args: Array[String]) {
SpinalVhdl(new CarryAdder(4))
}
}