Verilog - increment local parameter in generate block

Question

I'm getting an error in my Verilog generate block, on the line where it says j = j+1; stating `j is an unknown type'

genvar i;
generate
    localparam integer j = 0;
    for (i = 0; i < BUFFER; i=i+1) begin
        if((i%DATA_WIDTH) < (KERNEL_SIZE-1)) begin
            assign o_input_matrix[((j+1)*DATA_WIDTH)-1:j*DATA_WIDTH] = 
buffer[((i+1)*DATA_WIDTH)-1:i*DATA_WIDTH];
            j = j+1;
        end
    end
endgenerate

BUFFER, DATA_WIDTH, and KERNEL_SIZE are local parameters I have in my module.

I've been looking at ways I could have a 2nd parameter in my generate block, I've found out that I can only use genvar variables in a for loop, so I couldnt make a 2nd genvar variable for j.

I came across this question: Incrementing Multiple Genvars in Verilog Generate Statement

I tried basing my code of the 2nd answer, but my situation is slightly different because I'm only incrementing it in an if statement.

Any help would be appreciated.

Answer 1

You are going to have to make a function to define the value of j .

genvar i;
for (i = 0; i < BUFFER; i=i+1)
   if((i%DATA_WIDTH) < (KERNEL_SIZE-1)) begin
      localparam j = func(i);
      assign o_input_matrix[((j+1)*DATA_WIDTH)-1:j*DATA_WIDTH] = 
buffer[((i+1)*DATA_WIDTH)-1:i*DATA_WIDTH];
        end
    end
function integer func(integer ii);
   for (ii = 0;ii < BUFFER; ii++)
     if ((ii %DATA_WIDTH) < (KERNEL_SIZE-1)) ii++;
endfunction

Didn't try this, but hope it gets you close to what you want.