yosys/manual/PRESENTATION_ExAdv/macc_xilinx_test.v

module test1(a, b, c, d, e, f, y);
input [19:0] a, b, c;
input [15:0] d, e, f;
output [41:0] y;
assign y = a*b + c*d + e*f;
endmodule

module test2(a, b, c, d, e, f, y);
input [19:0] a, b, c;
input [15:0] d, e, f;
output [41:0] y;
assign y = a*b + (c*d + e*f);
endmodule