Subversion Repositories jt51

/*  This file is part of JT51.

    JT51 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.

    JT51 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 JT51.  If not, see <http://www.gnu.org/licenses/>.

        Author: Jose Tejada Gomez. Twitter: @topapate

        Version: 1.0

        Date: 27-10-2016

        */

`timescale 1ns / 1ps

module jt51_sum_op(

        input           clk,

        input           zero,

        input           en_ch,

        input   signed  [13:0] op_out,

        output reg signed       [15:0] out

);

reg     signed [18:0]    sum;

always @(posedge clk)

        if( zero ) begin

                sum <= en_ch ? op_out : 19'd0;

                if( sum[18:16]==3'd0 || sum[18:16]==3'b111 )

                        out <= sum[15:0];

                else

                        out<={ sum[18], {15{~sum[18]}}};

        end

        else

                if( en_ch ) sum <= sum + op_out;

endmodule