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_mul;

    output [31:0] out;

    input is_8_bit;

    input [15:0] a;

    input [15:0] b;

    input [15:0] flags_in;

    output [15:0] flags_out;

    input is_signed;

    begin

        flags_out = flags_in;

        flags_out[ZF_IDX] = 1'b0;

        out = 32'b0;

        if (!is_8_bit) begin

            if (is_signed)

                out[31:0] = {{16{a[15]}}, a} * {{16{b[15]}}, b};

            else

                out[31:0] = {16'b0, a} * {16'b0, b};

            flags_out[CF_IDX] = |out[31:16];

            flags_out[OF_IDX] = |out[31:16];

        end else begin

            if (is_signed)

                out = {16'b0, {{8{a[7]}}, a[7:0]} * {{8{b[7]}}, b[7:0]}};

            else

                out = {16'b0, {8'b0, a[7:0]} * {8'b0, b[7:0]}};

            flags_out[CF_IDX] = |out[15:8];

            flags_out[OF_IDX] = |out[15:8];

        end

    end

endtask