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

////                                                              ////

////  8051 internal ram                                           ////

////                                                              ////

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

////  http://www.opencores.org/cores/8051/                        ////

////                                                              ////

////  Description                                                 ////

////   256 bytes two port ram                                     ////

////                                                              ////

////  To Do:                                                      ////

////   nothing                                                    ////

////                                                              ////

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

////      - Simon Teran, simont@opencores.org                     ////

////                                                              ////

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

////                                                              ////

//// 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                     ////

////                                                              ////

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

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

//

//

// synopsys translate_off

`include "oc8051_timescale.v"

// synopsys translate_on

`include "oc8051_defines.v"

//

// two port ram

//

module oc8051_ram_256x8_two_bist (

                     clk,

                     rst,

                     rd_addr,

                     rd_data,

                     rd_en,

                     wr_addr,

                     wr_data,

                     wr_en,

                     wr

`ifdef OC8051_BIST

         ,

         scanb_rst,

         scanb_clk,

         scanb_si,

         scanb_so,

         scanb_en

`endif

                     );

input         clk,

              wr,

              rst,

              rd_en,

              wr_en;

input  [7:0]  wr_data;

input  [7:0]  rd_addr,

              wr_addr;

output [7:0]  rd_data;

`ifdef OC8051_BIST

input   scanb_rst;

input   scanb_clk;

input   scanb_si;

output  scanb_so;

input   scanb_en;

`endif

`ifdef OC8051_RAM_XILINX

  xilinx_ram_dp xilinx_ram(

        // read port

        .CLKA(clk),

        .RSTA(rst),

        .ENA(rd_en),

        .ADDRA(rd_addr),

        .DIA(8'h00),

        .WEA(1'b0),

        .DOA(rd_data),

        // write port

        .CLKB(clk),

        .RSTB(rst),

        .ENB(wr_en),

        .ADDRB(wr_addr),

        .DIB(wr_data),

        .WEB(wr),

        .DOB()

  );

  defparam

        xilinx_ram.dwidth = 8,

        xilinx_ram.awidth = 8;

`else

  `ifdef OC8051_RAM_VIRTUALSILICON

  `else

    `ifdef OC8051_RAM_GENERIC

      generic_dpram #(8, 8) oc8051_ram1(

        .rclk  ( clk            ),

        .rrst  ( rst            ),

        .rce   ( rd_en          ),

        .oe    ( 1'b1           ),

        .raddr ( rd_addr        ),

        .do    ( rd_data        ),

        .wclk  ( clk            ),

        .wrst  ( rst            ),

        .wce   ( wr_en          ),

        .we    ( wr             ),

        .waddr ( wr_addr        ),

        .di    ( wr_data        )

      );

    `else

      reg    [7:0]  rd_data;

      //

      // buffer

      reg    [7:0]  buff [0:256];

      //

      // writing to ram

      always @(posedge clk)

      begin

       if (wr)

          buff[wr_addr] <= #1 wr_data;

      end

      //

      // reading from ram

      always @(posedge clk or posedge rst)

      begin

        if (rst)

          rd_data <= #1 8'h0;

        else if ((wr_addr==rd_addr) & wr & rd_en)

          rd_data <= #1 wr_data;

        else if (rd_en)

          rd_data <= #1 buff[rd_addr];

      end

    `endif  //OC8051_RAM_GENERIC

  `endif    //OC8051_RAM_VIRTUALSILICON  

`endif      //OC8051_RAM_XILINX

endmodule