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//////////////////////////////////////////////////////////////////////

////                                                              ////

////  OMS 8051 cores common library Module                        ////

////                                                              ////

////  This file is part of the OMS 8051 cores project             ////

////  http://www.opencores.org/cores/oms8051mini/                 ////

////                                                              ////

////  Description                                                 ////

////  OMS 8051 definitions.                                       ////

////                                                              ////

////  To Do:                                                      ////

////    nothing                                                   ////

////                                                              ////

////  Author(s):                                                  ////

////      - Dinesh Annayya, dinesha@opencores.org                 ////

////                                                              ////

////  Revision : Nov 26, 2016                                     //// 

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source 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 Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

/*********************************************************************

** module: bit register

** description: infers a register, make it modular

 ***********************************************************************/

module bit_register (

                 //inputs

                 we,

                 clk,

                 reset_n,

                 data_in,

                 //outputs

                 data_out

                 );

//---------------------------------

// Reset Default value

//---------------------------------

parameter  RESET_DEFAULT = 1'h0;

  input  we;

  input  clk;

  input  reset_n;

  input  data_in;

  output data_out;

  reg    data_out;

  //infer the register

  always @(posedge clk or negedge reset_n)

    begin

      if (!reset_n)

        data_out <= RESET_DEFAULT;

      else if (we)

        data_out <= data_in;

    end // always @ (posedge clk or negedge reset_n)

endmodule // register

/*********************************************************************

** module: req register.

** description: This register is set by cpu writting 1 and reset by

                harward req = 1

 Note: When there is a clash between cpu and hardware, cpu is given higher

       priority

 ***********************************************************************/

module req_register (

                 //inputs

                 clk,

                 reset_n,

                 cpu_we,

                 cpu_req,

                 hware_ack,

                 //outputs

                 data_out

                 );

//---------------------------------

// Reset Default value

//---------------------------------

parameter  RESET_DEFAULT = 1'h0;

  input  clk      ;

  input  reset_n  ;

  input  cpu_we   ; // cpu write enable

  input  cpu_req  ; // CPU Request

  input  hware_ack; // Hardware Ack

  output data_out ;

  reg    data_out;

  //infer the register

  always @(posedge clk or negedge reset_n)

    begin

      if (!reset_n)

        data_out <= RESET_DEFAULT;

      else if (cpu_we & cpu_req) // Set on CPU Request

         data_out <= 1'b1;

      else if (hware_ack)  // Reset the flag on Hardware ack

         data_out <= 1'b0;

    end // always @ (posedge clk or negedge reset_n)

endmodule // register

/*********************************************************************

** module: req register.

** description: This register is cleared by cpu writting 1 and set by

                harward req = 1

 Note: When there is a clash between cpu and hardware,

       hardware is given higher priority

 ***********************************************************************/

module stat_register (

                 //inputs

                 clk,

                 reset_n,

                 cpu_we,

                 cpu_ack,

                 hware_req,

                 //outputs

                 data_out

                 );

//---------------------------------

// Reset Default value

//---------------------------------

parameter  RESET_DEFAULT = 1'h0;

  input  clk      ;

  input  reset_n  ;

  input  cpu_we   ; // cpu write enable

  input  cpu_ack  ; // CPU Ack

  input  hware_req; // Hardware Req

  output data_out ;

  reg    data_out;

  //infer the register

  always @(posedge clk or negedge reset_n)

    begin

      if (!reset_n)

        data_out <= RESET_DEFAULT;

      else if (hware_req)  // Set the flag on Hardware Req

         data_out <= 1'b1;

      else if (cpu_we & cpu_ack) // Clear on CPU Ack

         data_out <= 1'b0;

    end // always @ (posedge clk or negedge reset_n)

endmodule // register

/*********************************************************************

** copyright message here.

** module: generic register

***********************************************************************/

module  generic_register        (

              //List of Inputs

              we,

              data_in,

              reset_n,

              clk,

              //List of Outs

              data_out

              );

  parameter   WD               = 1;

  parameter   RESET_DEFAULT    = 0;

  input [WD-1:0]     we;

  input [WD-1:0]     data_in;

  input              reset_n;

  input              clk;

  output [WD-1:0]    data_out;

generate

  genvar i;

  for (i = 0; i < WD; i = i + 1) begin : gen_bit_reg

    bit_register #(RESET_DEFAULT[i]) u_bit_reg (

                .we         (we[i]),

                .clk        (clk),

                .reset_n    (reset_n),

                .data_in    (data_in[i]),

                .data_out   (data_out[i])

            );

  end

endgenerate

endmodule

/*********************************************************************

** copyright message here.

** module: generic register

***********************************************************************/

module  generic_intr_stat_reg   (

                 //inputs

                 clk,

                 reset_n,

                 reg_we,

                 reg_din,

                 hware_req,

                 //outputs

                 data_out

              );

  parameter   WD               = 1;

  parameter   RESET_DEFAULT    = 0;

  input [WD-1:0]     reg_we;

  input [WD-1:0]     reg_din;

  input [WD-1:0]     hware_req;

  input              reset_n;

  input              clk;

  output [WD-1:0]    data_out;

generate

  genvar i;

  for (i = 0; i < WD; i = i + 1) begin : gen_bit_reg

    stat_register #(RESET_DEFAULT[i]) u_bit_reg (

                 //inputs

                 . clk        (clk           ),

                 . reset_n    (reset_n       ),

                 . cpu_we     (reg_we[i]     ),

                 . cpu_ack    (reg_din[i]    ),

                 . hware_req  (hware_req[i]  ),

                 //outputs

                 . data_out  (data_out[i]    )

                 );

  end

endgenerate

endmodule