bullsandcows.v

module BullsAndCows(input wire [15:0] guess,
                    input wire [15:0] answer,
                    input wire checkEnable,
                    input wire [7:0] lcd_data_external,
                    output wire [3:0] strike,
                    output wire [3:0] ball,
                    output wire isFourStrike);

assign strike       = checkEnable ? count_strike(guess, answer) : 4'd0;
assign ball         = checkEnable ? count_ball(guess, answer) : 4'd0;
assign isFourStrike = (strike == 4'd4) ? 1'b1 : 1'b0;

function [3:0] count_strike;
    input [15:0] guess;
    input [15:0] answer;
    
    integer i;
    reg [3:0] count;
    
    begin
        count = 3'd0;
        for (i = 0; i < 4; i = i + 1) begin
            // $display("%d %h %b", guess[i*4 +: 4], guess[i*4 +: 4], guess[i*4 +: 4]);
            // $display("%d %h %b", answer[i*4 +: 4], answer[i*4 +: 4], answer[i*4 +: 4]);
            if (guess[i*4 +: 4] == answer[i*4 +: 4]) begin
                count = count + 1;
            end
        end
        count_strike = count;
    end
endfunction

function [3:0] count_ball;
    input [15:0] guess;
    input [15:0] answer;
    integer i, j;
    reg [3:0] count;
    
    begin
        count = 3'd0;
        for (i = 0; i < 4; i = i + 1) begin
            for (j = 0; j < 4; j = j + 1) begin
                if ((i ! = j) && (guess[i*4 +: 4] == answer[j*4 +: 4])) begin
                    count = count + 1;
                end
            end
        end
        count_ball = count;
    end
endfunction

endmodule