Subversion Repositories s80186

// Copyright Jamie Iles, 2017

//

// This file is part of s80x86.

//

// s80x86 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.

//

// s80x86 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 s80x86.  If not, see .

task do_sar;

    output [31:0] out;

    input is_8_bit;

    input [15:0] a;

    input [4:0] shift_count;

    input [15:0] flags_in;

    output [15:0] flags_out;

    output busy;

    input multibit_shift;

    begin

        flags_out = flags_in;

        out = {11'b0, shift_count, a};

        if (|shift_count || !multibit_shift) begin

            if (!is_8_bit)

                {out[15:0], flags_out[CF_IDX]} = $signed({a, 1'b0}) >>> 1'b1;

            else

                {out[7:0], flags_out[CF_IDX]} = $signed({a[7:0], 1'b0}) >>> 1'b1;

            flags_out[OF_IDX] = 0;

            shift_flags(flags_out, is_8_bit, out[15:0], a);

            out[31:16] = {11'b0, shift_count - 1'b1};

        end

        busy = multibit_shift && |out[20:16];

    end

endtask