/* memory.v - implementation of memory external to the 9086 CPU for testing purposes

   This file is part of the 9086 project.

   Copyright (c) 2023 Efthymios Kritikos

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

module mem(input [19:0] address,inout wire [15:0] data ,input rd,input wr,input cs);
reg [15:0] memory [0:8191];
initial begin
	string boot_code;
	if(!$value$plusargs("BOOT_CODE=%s",boot_code))begin
		$display("No boot code specified. Please add +BOOT_CODE=<path> to your vvp args");
		$finish;
	end
	$readmemh(boot_code, memory);
end

assign data = !rd & !cs ? memory[address]: 'hz;

always @(negedge wr) begin
	memory[address]=data;
end

endmodule