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_shl;

    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) begin

                {flags_out[CF_IDX], out[15:0]} = {1'b0, a} << 1'b1;

                flags_out[OF_IDX] = a[15] ^ out[15];

            end else begin

                {flags_out[CF_IDX], out[7:0]} = {1'b0, a[7:0]} << 1'b1;

                flags_out[OF_IDX] = a[7] ^ out[7];

            end

            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