/*                                                                      
 Copyright 2019 Blue Liang, liangkangnan@163.com
                                                                         
 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.                                          
 */

`include "defines.v"

// CPU core top module
module tinyriscv(

    input wire clk,
    input wire rst,

    output wire[`MemAddrBus] rib_ex_addr_o,
    input wire[`MemBus] rib_ex_data_i,
    output wire[`MemBus] rib_ex_data_o,
    output wire rib_ex_req_o,
    output wire rib_ex_we_o,

    output wire[`MemAddrBus] rib_pc_addr_o,
    input wire[`MemBus] rib_pc_data_i,

    input wire[`RegAddrBus] jtag_reg_addr_i,
    input wire[`RegBus] jtag_reg_data_i,
    input wire jtag_reg_we_i,
    output wire[`RegBus] jtag_reg_data_o,

    input wire rib_hold_flag_i,
    input wire jtag_halt_flag_i,
    input wire jtag_reset_flag_i,

    input wire[`INT_BUS] int_i

    );

    // pc_reg
	wire[`InstAddrBus] pc_pc_o;

    // if_id
	wire[`InstBus] if_inst_o;
    wire[`InstAddrBus] if_inst_addr_o;

    // id
    wire[`RegAddrBus] id_reg1_raddr_o;
    wire[`RegAddrBus] id_reg2_raddr_o;
    wire id_mem_req_o;
    wire[`InstBus] id_inst_o;
    wire[`InstAddrBus] id_inst_addr_o;
    wire[`RegBus] id_reg1_rdata_o;
    wire[`RegBus] id_reg2_rdata_o;
    wire id_reg_we_o;
    wire[`RegAddrBus] id_reg_waddr_o;
    wire[`MemAddrBus] id_csr_raddr_o;
    wire id_csr_we_o;
    wire[`RegBus] id_csr_rdata_o;
    wire[`MemAddrBus] id_csr_waddr_o;

    // id_ex
    wire[`InstBus] ie_inst_o;
    wire[`InstAddrBus] ie_inst_addr_o;
    wire ie_reg_we_o;
    wire[`RegAddrBus] ie_reg_waddr_o;
    wire[`RegBus] ie_reg1_rdata_o;
    wire[`RegBus] ie_reg2_rdata_o;
    wire ie_csr_we_o;
    wire[`MemAddrBus] ie_csr_waddr_o;
    wire[`RegBus] ie_csr_rdata_o;

    // ex
    wire[`MemBus] ex_mem_wdata_o;
    wire[`MemAddrBus] ex_mem_raddr_o;
    wire[`MemAddrBus] ex_mem_waddr_o;
    wire ex_mem_we_o;
    wire ex_mem_req_o;
    wire[`RegBus] ex_reg_wdata_o;
    wire ex_reg_we_o;
    wire[`RegAddrBus] ex_reg_waddr_o;
    wire ex_hold_flag_o;
    wire ex_jump_flag_o;
    wire[`InstAddrBus] ex_jump_addr_o;
    wire ex_div_start_o;
    wire[`RegBus] ex_div_dividend_o;
    wire[`RegBus] ex_div_divisor_o;
    wire[2:0] ex_div_op_o;
    wire[`RegAddrBus] ex_div_reg_waddr_o;
    wire[`INT_BUS] ex_int_flag_o;
    wire[`InstAddrBus] ex_int_return_addr_o;
    wire ex_clint_we_o;
    wire[`RegAddrBus] ex_clint_addr_o;
    wire[`RegBus] ex_clint_data_o;
    wire[`RegBus] ex_csr_wdata_o;
    wire ex_csr_we_o;
    wire[`MemAddrBus] ex_csr_waddr_o;

    // regs
    wire[`RegBus] regs_rdata1_o;
    wire[`RegBus] regs_rdata2_o;

    // csr reg
    wire[`RegBus] csr_data_o;

    // ctrl
    wire[`Hold_Flag_Bus] ctrl_hold_flag_o;
    wire ctrl_jump_flag_o;
    wire[`InstAddrBus] ctrl_jump_addr_o;

    // div
    wire[`DoubleRegBus] div_result_o;
	wire div_ready_o;
    wire div_busy_o;
    wire[2:0] div_op_o;
    wire[`RegAddrBus] div_reg_waddr_o;

    // clint
    wire[`RegBus] clint_data_o;


    assign rib_ex_addr_o = (ex_mem_we_o == `WriteEnable)? ex_mem_waddr_o: ex_mem_raddr_o;
    assign rib_ex_data_o = ex_mem_wdata_o;
    assign rib_ex_req_o = ex_mem_req_o | id_mem_req_o;
    assign rib_ex_we_o = ex_mem_we_o;

    assign rib_pc_addr_o = pc_pc_o;


    pc_reg u_pc_reg(
        .clk(clk),
        .rst(rst),
        .jtag_reset_flag_i(jtag_reset_flag_i),
        .pc_o(pc_pc_o),
        .hold_flag_i(ctrl_hold_flag_o),
        .jump_flag_i(ctrl_jump_flag_o),
        .jump_addr_i(ctrl_jump_addr_o)
    );

    ctrl u_ctrl(
        .rst(rst),
        .jump_flag_i(ex_jump_flag_o),
        .jump_addr_i(ex_jump_addr_o),
        .hold_flag_ex_i(ex_hold_flag_o),
        .hold_flag_rib_i(rib_hold_flag_i),
        .hold_flag_o(ctrl_hold_flag_o),
        .int_flag_i(ex_int_flag_o),
        .int_return_addr_i(ex_int_return_addr_o),
        .jump_flag_o(ctrl_jump_flag_o),
        .jump_addr_o(ctrl_jump_addr_o),
        .jtag_halt_flag_i(jtag_halt_flag_i)
    );

    regs u_regs(
        .clk(clk),
        .rst(rst),
        .we_i(ex_reg_we_o),
        .waddr_i(ex_reg_waddr_o),
        .wdata_i(ex_reg_wdata_o),
        .raddr1_i(id_reg1_raddr_o),
        .rdata1_o(regs_rdata1_o),
        .raddr2_i(id_reg2_raddr_o),
        .rdata2_o(regs_rdata2_o),
        .jtag_we_i(jtag_reg_we_i),
        .jtag_addr_i(jtag_reg_addr_i),
        .jtag_data_i(jtag_reg_data_i),
        .jtag_data_o(jtag_reg_data_o)
    );

    csr_reg u_csr_reg(
        .clk(clk),
        .rst(rst),
        .we_i(ex_csr_we_o),
        .raddr_i(id_csr_raddr_o),
        .waddr_i(ex_csr_waddr_o),
        .data_i(ex_csr_wdata_o),
        .data_o(csr_data_o)
    );

    if_id u_if_id(
        .clk(clk),
        .rst(rst),
        .inst_i(rib_pc_data_i),
        .inst_addr_i(pc_pc_o),
        .hold_flag_i(ctrl_hold_flag_o),
        .inst_o(if_inst_o),
        .inst_addr_o(if_inst_addr_o)
    );

    id u_id(
        .rst(rst),
        .inst_i(if_inst_o),
        .inst_addr_i(if_inst_addr_o),
        .reg1_rdata_i(regs_rdata1_o),
        .reg2_rdata_i(regs_rdata2_o),
        .ex_jump_flag_i(ex_jump_flag_o),
        .ex_int_flag_i(ex_int_flag_o),
        .reg1_raddr_o(id_reg1_raddr_o),
        .reg2_raddr_o(id_reg2_raddr_o),
        .mem_req_o(id_mem_req_o),
        .inst_o(id_inst_o),
        .inst_addr_o(id_inst_addr_o),
        .reg1_rdata_o(id_reg1_rdata_o),
        .reg2_rdata_o(id_reg2_rdata_o),
        .reg_we_o(id_reg_we_o),
        .reg_waddr_o(id_reg_waddr_o),
        .csr_rdata_i(csr_data_o),
        .csr_raddr_o(id_csr_raddr_o),
        .csr_we_o(id_csr_we_o),
        .csr_rdata_o(id_csr_rdata_o),
        .csr_waddr_o(id_csr_waddr_o)
    );

    id_ex u_id_ex(
        .clk(clk),
        .rst(rst),
        .inst_i(id_inst_o),
        .inst_addr_i(id_inst_addr_o),
        .reg_we_i(id_reg_we_o),
        .reg_waddr_i(id_reg_waddr_o),
        .reg1_rdata_i(id_reg1_rdata_o),
        .reg2_rdata_i(id_reg2_rdata_o),
        .hold_flag_i(ctrl_hold_flag_o),
        .inst_o(ie_inst_o),
        .inst_addr_o(ie_inst_addr_o),
        .reg_we_o(ie_reg_we_o),
        .reg_waddr_o(ie_reg_waddr_o),
        .reg1_rdata_o(ie_reg1_rdata_o),
        .reg2_rdata_o(ie_reg2_rdata_o),
        .csr_we_i(id_csr_we_o),
        .csr_waddr_i(id_csr_waddr_o),
        .csr_rdata_i(id_csr_rdata_o),
        .csr_we_o(ie_csr_we_o),
        .csr_waddr_o(ie_csr_waddr_o),
        .csr_rdata_o(ie_csr_rdata_o)
    );

    ex u_ex(
        .rst(rst),
        .inst_i(ie_inst_o),
        .inst_addr_i(ie_inst_addr_o),
        .reg_we_i(ie_reg_we_o),
        .reg_waddr_i(ie_reg_waddr_o),
        .reg1_rdata_i(ie_reg1_rdata_o),
        .reg2_rdata_i(ie_reg2_rdata_o),
        .mem_rdata_i(rib_ex_data_i),
        .mem_wdata_o(ex_mem_wdata_o),
        .mem_raddr_o(ex_mem_raddr_o),
        .mem_waddr_o(ex_mem_waddr_o),
        .mem_we_o(ex_mem_we_o),
        .mem_req_o(ex_mem_req_o),
        .reg_wdata_o(ex_reg_wdata_o),
        .reg_we_o(ex_reg_we_o),
        .reg_waddr_o(ex_reg_waddr_o),
        .clint_we_o(ex_clint_we_o),
        .clint_addr_o(ex_clint_addr_o),
        .clint_data_o(ex_clint_data_o),
        .clint_data_i(clint_data_o),
        .int_return_addr_o(ex_int_return_addr_o),
        .hold_flag_o(ex_hold_flag_o),
        .jump_flag_o(ex_jump_flag_o),
        .jump_addr_o(ex_jump_addr_o),
        .int_flag_i(int_i),
        .int_flag_o(ex_int_flag_o),
        .div_ready_i(div_ready_o),
        .div_result_i(div_result_o),
        .div_busy_i(div_busy_o),
        .div_op_i(div_op_o),
        .div_reg_waddr_i(div_reg_waddr_o),
        .div_start_o(ex_div_start_o),
        .div_dividend_o(ex_div_dividend_o),
        .div_divisor_o(ex_div_divisor_o),
        .div_op_o(ex_div_op_o),
        .div_reg_waddr_o(ex_div_reg_waddr_o),
        .csr_we_i(ie_csr_we_o),
        .csr_waddr_i(ie_csr_waddr_o),
        .csr_rdata_i(ie_csr_rdata_o),
        .csr_wdata_o(ex_csr_wdata_o),
        .csr_we_o(ex_csr_we_o),
        .csr_waddr_o(ex_csr_waddr_o)
    );

    div u_div(
        .clk(clk),
        .rst(rst),
        .dividend_i(ex_div_dividend_o),
        .divisor_i(ex_div_divisor_o),
        .start_i(ex_div_start_o),
        .op_i(ex_div_op_o),
        .reg_waddr_i(ex_div_reg_waddr_o),
        .result_o(div_result_o),
        .ready_o(div_ready_o),
        .busy_o(div_busy_o),
        .op_o(div_op_o),
        .reg_waddr_o(div_reg_waddr_o)
    );

    clint u_clint(
        .clk(clk),
        .rst(rst),
        .we_i(ex_clint_we_o),
        .addr_i(ex_clint_addr_o),
        .data_i(ex_clint_data_o),
        .data_o(clint_data_o)
    );

endmodule