Prefix computation network

[raducrv]

Hi ,

I am trying to make synthesize the circuit in the figure which is a prefix computation network with AND gate . I have done the fallowing code in Verilog but i have some error about the indices

The idea is to use parametrisable recursion

THE CODE:

module PCN #(parameter n = 4)
( output [n-1:0] out ,
input [n-1:0] in );


wire [n/2-1:0] wire0; //wires to PCN(n/2)
wire [n/2-1:0] wire1; //wires from PCN(n/2)


genvar i;
generate
if (n == 2) begin
assign out[0] = in[0];
and and1(out[n-1], in[0], in[n-1]);
end
else
begin
//up ands
for (i=0; i<n/2; i=i+1) begin:up_ands
and and1(wire0, in[i*2], in[i*2+1]);
end

//PCN(n/2) module
PCN #(.n(n/2)) PCN0(.out(wire1),
.in (wire0));

//down ands
for (i=1; i<(n/2-1); i=i+1) begin: down_ands
and and1(out0[i*2+3], in[i*2+2], wire1);
assign zout[i*2+1] = wire1;
end

//first and last input
assign out[0] = in[0];
assign out[n-1] = wire1[n/2-1];
end

endgenerate
endmodule