Anonymous struct export to top

Question

I have an input SystemVerilog RTL like this :

typedef struct packed {
  logic [1:0][3:0] a;
  struct packed {
    logic [4:0] b;
    logic c;
    logic [1:0] d;
  }  e; // anonymous packed struct field
} s0;

module ip( input s0  p );
endmodule

module top();
endmodule

Using some scripts I want :

• To export (from ip to top) the the field p.e, i.e generate something like :

  typedef struct packed { 
       logic [4:0] b; 
       logic c; 
       logic [1:0] d; 
  } s0_e; 
  module top(s0_e p);
  

• Then connect ip inside top with : ip.p.e <->top.p (and ip.p.a left unconnected)

Given that p.e is an anonymous struct I am wondering what would be the correct syntax to do it? do I need to create a new typedef as above ?

Answer 1

In general, you should avoid using anonymous strucures if you want to share information between modules. But since this is a packed struct, there is no type safety and it doesn't matter if you declare the types independently. They just need to have the same number of bits.

typedef struct packed {
    logic [4:0] b;
    logic c;
    logic [1:0] d;
}  et; 
typedef struct packed {
  logic [1:0][3:0] a;
  et e;}
s0;

module ip( input wire s0  p );
endmodule

module top(input wire et p); 

  s0 signal;
  assign signal.e = p;
  
  ip inst(signal);
  
endmodule