Subversion Repositories s80186

// Copyright Jamie Iles, 2017

//

// This file is part of s80x86.

//

// s80x86 is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// s80x86 is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with s80x86.  If not, see .

module BIOSControlRegister(input logic clk,

                           input logic reset,

                           input logic cs,

                           output logic [15:0] data_m_data_out,

                           input logic [15:0] data_m_data_in,

                           input logic data_m_wr_en,

                           input logic data_m_access,

                           output logic data_m_ack,

                           output logic bios_enabled);

always_ff @(posedge clk) begin

    data_m_data_out <= data_m_access && cs && !data_m_wr_en ?

        {15'b0, bios_enabled} : 16'b0;

    data_m_ack <= data_m_access && cs;

end

always_ff @(posedge clk or posedge reset) begin

    if (reset)

        bios_enabled <= 1'b1;

    else if (cs && data_m_access && data_m_wr_en)

        bios_enabled <= data_m_data_in[0];

end

endmodule