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 .

module Flags(input logic clk,

             input logic reset,

             // verilator lint_off UNUSED

             input logic [15:0] flags_in,

             // verilator lint_on UNUSED

             input logic [8:0] update_flags,

             output logic [15:0] flags_out);

reg C, P, A, Z, S, T, I, D, O;

assign flags_out = {4'b1111, O, D, I, T, S, Z, 1'b0, A, 1'b0, P, 1'b1, C};

always_ff @(posedge clk or posedge reset) begin

    if (reset) begin

        C <= 1'b0;

        P <= 1'b0;

        A <= 1'b0;

        Z <= 1'b0;

        S <= 1'b0;

        T <= 1'b0;

        I <= 1'b0;

        D <= 1'b0;

        O <= 1'b0;

    end else begin

        C <= update_flags[UpdateFlags_CF] ? flags_in[CF_IDX] : C;

        P <= update_flags[UpdateFlags_PF] ? flags_in[PF_IDX] : P;

        A <= update_flags[UpdateFlags_AF] ? flags_in[AF_IDX] : A;

        Z <= update_flags[UpdateFlags_ZF] ? flags_in[ZF_IDX] : Z;

        S <= update_flags[UpdateFlags_SF] ? flags_in[SF_IDX] : S;

        T <= update_flags[UpdateFlags_TF] ? flags_in[TF_IDX] : T;

        I <= update_flags[UpdateFlags_IF] ? flags_in[IF_IDX] : I;

        D <= update_flags[UpdateFlags_DF] ? flags_in[DF_IDX] : D;

        O <= update_flags[UpdateFlags_OF] ? flags_in[OF_IDX] : O;

    end

end

endmodule