or1200_dpram_256x32.v

or1200开源risc cpu的verilog描述实现

//////////////////////////////////////////////////////////////////////
////                                                              ////
////  Generic Double-Port Synchronous RAM                         ////
////                                                              ////
////  This file is part of memory library available from          ////
////  http://www.opencores.org/cvsweb.shtml/generic_memories/     ////
////                                                              ////
////  Description                                                 ////
////  This block is a wrapper with common double-port             ////
////  synchronous memory interface for different                  ////
////  types of ASIC and FPGA RAMs. Beside universal memory        ////
////  interface it also provides behavioral model of generic      ////
////  double-port synchronous RAM.                                ////
////  It should be used in all OPENCORES designs that want to be  ////
////  portable accross different target technologies and          ////
////  independent of target memory.                               ////
////                                                              ////
////  Supported ASIC RAMs are:                                    ////
////                                                              ////
////  Supported FPGA RAMs are:                                    ////
////  - Xilinx Virtex RAMB16                                      ////
////  - Xilinx Virtex RAMB4                                       ////
////                                                              ////
////  To Do:                                                      ////
////   - add additional RAMs                                      ////
////   - xilinx rams need external tri-state logic                ////
////                                                              ////
////  Author(s):                                                  ////
////      - Nir  Mor, [e-mail]                          ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2005 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
//

// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"

module or1200_dpram_256x32(
	// Generic synchronous double-port RAM interface
	clk_a, rst_a, ce_a, oe_a, addr_a, do_a,
	clk_b, rst_b, ce_b, we_b, addr_b, di_b
);

//
// Default address and data buses width
//
parameter aw = 8;
parameter dw = 32;

//
// Generic synchronous double-port RAM interface
//
input			clk_a;	// Clock
input			rst_a;	// Reset
input			ce_a;	// Chip enable input
input			oe_a;	// Output enable input
input 	[aw-1:0]	addr_a;	// address bus inputs
output	[dw-1:0]	do_a;	// output data bus
input			clk_b;	// Clock
input			rst_b;	// Reset
input			ce_b;	// Chip enable input
input			we_b;	// Write enable input
input 	[aw-1:0]	addr_b;	// address bus inputs
input	[dw-1:0]	di_b;	// input data bus


`ifdef OR1200_XILINX_RAMB4

//
// Instantiation of FPGA memory:
//
// Virtex/Spartan2
//

//
// Block 0
//
RAMB4_S16_S16 ramb4_s16_0(
	.CLKA(clk_a),
	.RSTA(rst_a),
	.ADDRA(addr_a),
	.DIA(16'h0000),
	.ENA(ce_a),
	.WEA(1'b0),
	.DOA(do_a[15:0]),

	.CLKB(clk_b),
	.RSTB(rst_b),
	.ADDRB(addr_b),
	.DIB(di_b[15:0]),
	.ENB(ce_b),
	.WEB(we_b),
	.DOB()
);

//
// Block 1
//
RAMB4_S16_S16 ramb4_s16_1(
	.CLKA(clk_a),
	.RSTA(rst_a),
	.ADDRA(addr_a),
	.DIA(16'h0000),
	.ENA(ce_a),
	.WEA(1'b0),
	.DOA(do_a[31:16]),

	.CLKB(clk_b),
	.RSTB(rst_b),
	.ADDRB(addr_b),
	.DIB(di_b[31:16]),
	.ENB(ce_b),
	.WEB(we_b),
	.DOB()
);

`else

`ifdef OR1200_XILINX_RAMB16

//
// Instantiation of FPGA memory:
//
// Virtex4/Spartan3E
//
// Added By Nir Mor
//

RAMB16_S36_S36 ramb16_s36_s36(
	.CLKA(clk_a),
	.SSRA(rst_a),
	.ADDRA({1'b0, addr_a}),
	.DIA(32'h00000000),
	.DIPA(4'h0),
 	.ENA(ce_a),
	.WEA(1'b0),
	.DOA(do_a),
	.DOPA(),

	.CLKB(clk_b),
	.SSRB(rst_b),
	.ADDRB({1'b0, addr_b}),
	.DIB(di_b),
	.DIPB(4'h0),
	.ENB(ce_b),
	.WEB(we_b),
	.DOB(),
	.DOPB()
);

`else

//
// Generic double-port synchronous RAM model
//

//
// Generic RAM's registers and wires
//
reg	[dw-1:0]	mem [(1<<aw)-1:0];	// RAM content
reg	[aw-1:0]	addr_a_reg;		// RAM address registered

//
// Data output drivers
//
assign do_a = (oe_a) ? mem[addr_a_reg] : {dw{1'b0}};

//
// RAM read
//
always @(posedge clk_a or posedge rst_a)
	if (rst_a)
		addr_a_reg <= #1 {aw{1'b0}};
	else if (ce_a)
		addr_a_reg <= #1 addr_a;

//
// RAM write
//
always @(posedge clk_b)
	if (ce_b && we_b)
		mem[addr_b] <= #1 di_b;

`endif	// !OR1200_XILINX_RAMB16
`endif	// !OR1200_XILINX_RAMB4
endmodule