Structs

Structs group related wires together, enforcing identical timing and, when used as module IO, direction. They can also be parameterized.

Definition

Structs are defined using the struct keyword, followed by the name and map of fields. Fields are of the form name: type, where type is an expression that resolves to a LogicType value.

struct MyStruct {
  a: Bits(32),
  b: Bits(32),
}

struct MyParameterizedStruct(t: LogicType) {
  a: Bits(32),
  b: t,
}

Use

For unparameterized structs, the name becomes a LogicType value and can be used directly. For parameterized structs, the name is a function reference to be called with values for the parameters.

logic val(0): MyStruct;

logic parameterized_val(0): MyParameterizedStruct(Int(32));

Accessing fields of a struct works as in any other language, and they can be assigned or read:

assign val.a = some_data;
assign some_value = val.a;

Structs can also be assigned as a whole:

assign val = another_instance_of_MyStruct;

Structs can be instantiated with a map of field names to values:

assign my_struct = .{
  a: some_data,
  b: some_other_data,
};