// Copyright 2021 cpu-dev
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

module regfile(rd_addr, rs_addr, w_data, w_en, rd_data, rs_data, clock, intr_en);
    input [1:0] rd_addr, rs_addr;
    input [7:0] w_data;
    input w_en;
    input clock;
    input intr_en;
    output [7:0] rs_data, rd_data;

    reg [7:0] register[0:3];
    reg [7:0] intr_register[0:3];

    assign rd_data = intr_en ? intr_register[rd_addr] : register[rd_addr];
    assign rs_data = intr_en ? intr_register[rs_addr] : register[rs_addr];
    always @(posedge clock) begin
        if(intr_en) begin
            if(w_en == 1) begin
                intr_register[rd_addr] <= w_data;
            end else begin
                intr_register[rd_addr] <= intr_register[rd_addr];
            end
        end else begin
            if(w_en == 1) begin
                register[rd_addr] <= w_data;
            end else begin
                register[rd_addr] <= register[rd_addr];
            end
        end
    end
endmodule