// https://raw.githubusercontent.com/smunaut/ice40-playground/68ac87f6c458712a41d5b8e305d222849233ff00/cores/misc/rtl/ram_sdp.v

/*
 * ram_sdp.v
 *
 * vim: ts=4 sw=4
 *
 * Copyright (C) 2019  Sylvain Munaut <tnt@246tNt.com>
 * All rights reserved.
 *
 * BSD 3-clause, see LICENSE.bsd
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

`default_nettype none

module ram_sdp #(
	parameter integer AWIDTH = 9,
	parameter integer DWIDTH = 8
)(
	input  wire [AWIDTH-1:0] wr_addr,
	input  wire [DWIDTH-1:0] wr_data,
	input  wire wr_ena,

	input  wire [AWIDTH-1:0] rd_addr,
	output reg  [DWIDTH-1:0] rd_data,
	input  wire rd_ena,

	input  wire clk
);
	// Signals
	reg [DWIDTH-1:0] ram [(1<<AWIDTH)-1:0];

`ifdef SIM
	integer i;
	initial
		for (i=0; i<(1<<AWIDTH); i=i+1)
			ram[i] = 0;
`endif

	always @(posedge clk)
	begin
		// Read
		if (rd_ena)
			rd_data <= ram[rd_addr];

		// Write
		if (wr_ena)
			ram[wr_addr] <= wr_data;
	end

endmodule // ram_sdp
