plic_comparator.sv

// Copyright 2018 ETH Zurich and University of Bologna.
// Copyright and related rights are licensed under the Solderpad Hardware
// License, Version 0.51 (the "License"); you may not use this file except in
// compliance with the License.  You may obtain a copy of the License at
// http://solderpad.org/licenses/SHL-0.51. Unless required by applicable law
// or agreed to in writing, software, hardware and materials distributed under
// this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
//
//-------------------------------------------------------------------------------
//-- Title      : Comperator
//-- File       : plic_comperator.sv
//-- Author     : Gian Marti      <gimarti.student.ethz.ch>
//-- Author     : Thomas Kramer   <tkramer.student.ethz.ch>
//-- Author     : Thomas E. Benz  <tbenz.student.ethz.ch>
//-- Company    : Integrated Systems Laboratory, ETH Zurich
//-- Created    : 2018-03-31
//-- Last update: 2018-03-31
//-- Platform   : ModelSim (simulation), Synopsys (synthesis)
//-- Standard   : SystemVerilog IEEE 1800-2012
//-------------------------------------------------------------------------------
//-- Description: Comparator
//-------------------------------------------------------------------------------
//-- Revisions  :
//-- Date        Version  Author  Description
//-- 2018-03-31  2.0      tbenz   Created header
//-------------------------------------------------------------------------------

// find larger operand (value and identifier)
// chooses the left operand on equality
module plic_comparator #(
    parameter int ID_BITWIDTH       = -1,
    parameter int PRIORITY_BITWIDTH = -1
)(
    input  logic [PRIORITY_BITWIDTH-1:0]  left_priority_i,
    input  logic [PRIORITY_BITWIDTH-1:0]  right_priority_i,
    input  logic [ID_BITWIDTH-1:0      ]  left_identifier_i,
    input  logic [ID_BITWIDTH-1:0      ]  right_identifier_i,
    output logic [PRIORITY_BITWIDTH-1:0]  larger_priority_o,
    output logic[ ID_BITWIDTH-1:0      ]  identifier_of_larger_o
);

    always_comb begin : proc_compare
        if (left_priority_i >= right_priority_i) begin
            larger_priority_o      = left_priority_i;
            identifier_of_larger_o = left_identifier_i;
        end else begin
            larger_priority_o      = right_priority_i;
            identifier_of_larger_o = right_identifier_i;
        end
    end

    //pragma translate_off
    `ifndef VERILATOR
    initial begin
        assert(ID_BITWIDTH       > 0)   else $error("ID_BITWIDTH has to be larger than 0");
        assert(PRIORITY_BITWIDTH > 0)   else $error("PRIORITY_BITWIDTH has to be larger than 0");
    end
    `endif
    //pragma translate_on

endmodule