//======================================================================
//
// rng_selector.v
// -----------------
// Top level wrapper that creates the Cryptech coretest system.
// The wrapper contains instances of external interface, coretest
// and the core to be tested. And if more than one core is
// present the wrapper also includes address and data muxes.
//
//
// Authors: Joachim Strombergson, Paul Selkirk, Pavel Shatov
// Copyright (c) 2014-2015, NORDUnet A/S All rights reserved.
//
// 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 NORDUnet 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 THE COPYRIGHT
// HOLDER OR CONTRIBUTORS 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.
//
//======================================================================
module rng_selector
(
input wire sys_clk,
input wire sys_rst,
input wire sys_ena,
input wire [13: 0] sys_eim_addr,
input wire sys_eim_wr,
input wire sys_eim_rd,
output wire [31 : 0] sys_read_data,
input wire [31 : 0] sys_write_data
);
//
// Output Register
//
reg [31: 0] tmp_read_data;
assign sys_read_data = tmp_read_data;
/* So far we have no RNG cores, let's make some dummy 32-bit registers here
* to prevent ISE from complaining that we don't use input ports.
*/
reg [31: 0] reg_dummy_first;
reg [31: 0] reg_dummy_second;
reg [31: 0] reg_dummy_third;
always @(posedge sys_clk)
//
if (sys_rst) begin
reg_dummy_first <= {8{4'hA}};
reg_dummy_second <= {8{4'hB}};
reg_dummy_third <= {8{4'hC}};
end else if (sys_ena) begin
//
if (sys_eim_wr) begin
//
// WRITE handler
//
case (sys_eim_addr)
14'd0: reg_dummy_first <= sys_write_data;
14'd1: reg_dummy_second <= sys_write_data;
14'd2: reg_dummy_third <= sys_write_data;
endcase
//
end
//
if (sys_eim_rd) begin
//
// READ handler
//
case (sys_eim_addr)
14'd0: tmp_read_data <= reg_dummy_first;
14'd1: tmp_read_data <= reg_dummy_second;
14'd2: tmp_read_data <= reg_dummy_third;
//
default:
tmp_read_data <= {32{1'b0}}; // read non-existent locations as zeroes
endcase
//
end
//
end
endmodule
//======================================================================
// EOF core_selector.v
//======================================================================
