path: root/rtl/modexpng_mmm_pad.v

module modexpng_mmm_pad
(
    clk, rst_n,
    fsm_state,
    load_xy_addr_lsb,
    pad_x_rd_addr, pad_y_rd_addr,
    pad_x_rd_ena,  pad_y_rd_ena,
    pad_x_rd_dout, pad_y_rd_dout,
    load_x_din,    load_y_din
);


    //
    // Includes
    //
    `include "modexpng_parameters.vh"
    //`include "modexpng_parameters_x8.vh"
    `include "modexpng_mmm_fsm.vh"


    //
    // Parameters
    //
    parameter INDEX_WIDTH = 6;
    
    
    //
    // Ports
    //
    input                        clk;
    input                        rst_n;
    input  [FSM_STATE_WIDTH-1:0] fsm_state;

    input [INDEX_WIDTH-1:0] load_xy_addr_lsb;
    
    input [WORD_WIDTH-1:0] load_x_din;
    input [WORD_WIDTH-1:0] load_y_din;
    
    input [INDEX_WIDTH-1:0] pad_x_rd_addr;
    input [INDEX_WIDTH-1:0] pad_y_rd_addr;
    
    input                   pad_x_rd_ena;
    input                   pad_y_rd_ena;
    
    output [WORD_WIDTH-1:0] pad_x_rd_dout;
    output [WORD_WIDTH-1:0] pad_y_rd_dout;
    
 
    //
    // Registers
    //
    reg [INDEX_WIDTH-1:0] pad_x_wr_addr;
    reg [INDEX_WIDTH-1:0] pad_y_wr_addr;
    reg                   pad_x_wr_ena;
    reg                   pad_y_wr_ena;
    reg [ WORD_WIDTH-1:0] pad_x_wr_din;
    reg [ WORD_WIDTH-1:0] pad_y_wr_din;
        
    bram_1wo_1ro_readfirst_ce #
    (
        .MEM_WIDTH      (WORD_WIDTH),
        .MEM_ADDR_BITS  (INDEX_WIDTH)
    )
    pad_x
    (
        .clk        (clk),

        .a_addr     (pad_x_wr_addr),
        .a_en       (pad_x_wr_ena),
        .a_wr       (pad_x_wr_ena),
        .a_in       (pad_x_wr_din),
        .a_out      (), // unused

        .b_addr     (pad_x_rd_addr),
        .b_en       (pad_x_rd_ena),
        .b_out      (pad_x_rd_dout)
    );    

    bram_1wo_1ro_readfirst_ce #
    (
        .MEM_WIDTH      (WORD_WIDTH),
        .MEM_ADDR_BITS  (INDEX_WIDTH)
    )
    pad_y
    (
        .clk        (clk),

        .a_addr     (pad_y_wr_addr),
        .a_en       (pad_y_wr_ena),
        .a_wr       (pad_y_wr_ena),
        .a_in       (pad_y_wr_din),
        .a_out      (), // unused

        .b_addr     (pad_y_rd_addr),
        .b_en       (pad_y_rd_ena),
        .b_out      (pad_y_rd_dout)
    );    
  

    always @(posedge clk)
        //
        case (fsm_state)
            //
            FSM_STATE_LOAD_T1T2_3: begin
                pad_x_wr_addr <= load_xy_addr_lsb;
                pad_y_wr_addr <= load_xy_addr_lsb;
            end
            //
            default: begin
                pad_x_wr_addr <= {INDEX_WIDTH{1'bX}};
                pad_y_wr_addr <= {INDEX_WIDTH{1'bX}};
            end
            //
        endcase

    always @(posedge clk)
        //
        case (fsm_state)
            //
            FSM_STATE_LOAD_T1T2_3: begin
                pad_x_wr_din <= load_x_din;
                pad_y_wr_din <= load_y_din;
            end
            //
            default: begin
                pad_x_wr_din <= load_x_din;
                pad_y_wr_din <= load_y_din;
            end
            //
        endcase
        
  
    always @(posedge clk or negedge rst_n)
        //
        if (!rst_n) begin
            pad_x_wr_ena <= 1'b0;
            pad_y_wr_ena <= 1'b0;
        end else case (fsm_state)
            //
            FSM_STATE_LOAD_T1T2_3: begin
                pad_x_wr_ena <= 1'b1;
                pad_y_wr_ena <= 1'b1;
            end
            //
            default: begin
                pad_x_wr_ena <= 1'b0;
                pad_y_wr_ena <= 1'b0;
            end
            //
        endcase


endmodule