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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