Game of life

conway.sv

module top_module(
    input clk,
    input load,
    input [255:0] data,
    output [255:0] q); 

    function bit[3:0] inc(input int x);
        return x + 1;
    endfunction

    function bit[3:0] dec(input int x);
        return x - 1;
    endfunction

    wire [15:0] row[16];
    always @(*)
        for (int r = 0; r < 16; r++)
            row[r] = (load) ? data[16*r+:16] : q[16*r+:16];

    genvar r;
    generate
        for (r = 0; r < 16; r=r+1) begin : gen
            conway16 inst(clk, load, row[inc(r)], row[r], row[dec(r)], q[(16*r)+:16]);
        end
    endgenerate
endmodule

module conway16(
    input clk,
    input load,
    input [15:0] U,
    input [15:0] C,
    input [15:0] D,
    output [15:0] q);
    
    function bit[3:0] inc(input int x);
        return x + 1;
    endfunction

    function bit[3:0] dec(input int x);
        return x - 1;
    endfunction

    //  17  16 | 31
    //   1   0 | 15
    // --------+
    // 241 240  255
    genvar c;
    generate
        for (c = 0; c < 16; c = c+1) begin : gen
            conway1 inst(clk, load,
                         U[inc(c)], U[c], U[dec(c)],
                         C[inc(c)], C[c], C[dec(c)],
                         D[inc(c)], D[c], D[dec(c)],
                         q[c]);
        end
    endgenerate
endmodule

module conway1(
    input clk,
    input load,
    input UL, U, UR,
    input CL, C, CR,
    input DL, D, DR,
    output reg q);
    
    wire q_next;
    wire [2:0] sum;

    assign sum = UL + U + UR + CL + CR + DL + D + DR;
    always @(*)
        case (sum)
            3'd2: q_next <= C;
            3'd3: q_next = 1'b1;
            default:
                  q_next = 1'b0;
        endcase
        
    always @(posedge clk)
        if (load)
            q <= C;
        else
            q <= q_next;
endmodule