//For system_regfile, the ROreg: isr is updated by the intrrupt_status 
//at last clk_posedge due to dff(status->irisr) & dff(irisr->isr)
class sys_refmodel;

  virtual sysreg_if		vif;
  virtual spi_if		wif;
  virtual sram_if#(25,32)	xif;

    //interrupt buffer
    bit[31:0] 			irisr    = 32'b0;
    bit				irisr_clr = 1'b0;

    //poor-quality register model
    bit[31:0]   		rm[17];

    //members to be sent to scoreboard
    int 			rst_error[5];
    bit[31:0]   		dout[$];
    sysreg_trans		sysout[$];

  

  function new();
  endfunction
  extern task do_imitate();
  extern task RWreg_write	(bit[24:0] addr,bit[32:0] din);
  extern task ROreg_update	(bit[24:0] addr			     );
  extern task reg_read		(bit[24:0] addr			     );
  extern task rst_check		(bit[31:0] rst_time,int i	 );
  extern task output_trace	(bit[24:0] addr				 );

endclass : sys_refmodel 

task sys_refmodel::do_imitate();
    
    int		i=0,j=0;
    rm[ 0] = 32'h41574743;    //IDR
    rm[ 1] = 32'h55535443;    //VIDR
    rm[ 2] = 32'h20220831;    //DATER
    rm[ 3] = 32'h00000001;    //VERR
    rm[ 4] = 32'h01234567;    //TESTR
    rm[ 5] = 32'b0;           //IMR
    rm[ 6] = 32'b0;           //ISR
    rm[ 7] = 32'd300;         //SFRTR
    rm[ 8] = 32'd0;           //SFRR
    rm[ 9] = 32'd0;           //CH0RSTR
    rm[10] = 32'd0;           //CH1RSTR
    rm[11] = 32'd0;           //CH2RSTR
    rm[12] = 32'd0;           //CH3RSTR
    rm[13] = 32'd0;           //DBGCFGR
    rm[14] = 32'd0;           
    rm[15] = 32'd0;           
    rm[16] = 32'd0;           //MISR

    fork


      while(1) begin:  write_reg_RW
	
 	    @(negedge xif.wren);

	    RWreg_write(xif.addr,xif.din);

      end:  write_reg_RW



      while(1) begin:  update_reg_RO

            ROreg_update(xif.addr);

      end:  update_reg_RO


      while(1) begin: read_reg

	    @(negedge xif.rden);
            repeat(3) @(posedge xif.clk);

	    reg_read(xif.addr);

      end:  read_reg



     begin:  rst_port	

        for(i=0;i<5;i++) begin
          automatic int rst_i = i;
          fork
            while(1) begin
	      @(negedge xif.wren);
	      if(xif.addr[24: 2]==23'h08+rst_i)
	        rst_check(rm[7],rst_i);
            end
          join_none
        end

        wait fork;

      end:  rst_port


      while(1) begin:  dbg_port
	
 	    @(negedge xif.wren);

	    output_trace(xif.addr);

      end:  dbg_port


    join

endtask: do_imitate



task sys_refmodel::RWreg_write(bit[24:0] addr,bit[32:0] din);

  	//delay caused by decoder
  	@(posedge wif.clk);

  	case(addr[24: 2])
  	  23'h04:	rm[ 4]	 = din;                        //TESTR
  	  23'h05:	rm[ 5]	 = din;                        //IMR
  	  23'h07:	rm[ 7]	 = din;                        //SFRTR
	  23'h0d:	rm[13]   = {rm[13][31:6],din[5:0]};    //DBGCFGR
  	endcase
 // $display("addr:%0h",addr);
 // $display("rm[%d]:%h",addr[24:2],rm[addr[24: 2]]);
 // $display("din:%h",din);

endtask:  RWreg_write



task sys_refmodel::ROreg_update(bit[24:0] addr);

	//irisr->isr
	@(posedge wif.clk);

	rm[ 6] = irisr	;
	rm[14] = irisr & rm[5]	;

	//intr_status->irisr
	if(irisr_clr)
	  irisr = vif.status;
	else
      	  irisr = irisr | vif.status	;	

endtask:  ROreg_update


task sys_refmodel::reg_read(bit[24:0] addr);

	
	case(addr[24: 2])
	  23'h00:  	dout.push_back(rm[ 0]);    //IDR
	  23'h01:  	dout.push_back(rm[ 1]);    //VIDR
	  23'h02:  	dout.push_back(rm[ 2]);    //DATER
	  23'h03:  	dout.push_back(rm[ 3]);    //VERR
	  23'h04:  	dout.push_back(rm[ 4]);    //TESTR
	  23'h05:  	dout.push_back(rm[ 5]);    //IMm
	  23'h06:  	dout.push_back(rm[ 6]);    //ISR
	  23'h07:  	dout.push_back(rm[ 7]);    //SFRTR
	  23'h08:  	dout.push_back(rm[ 8]);    //SFRR
	  23'h09:  	dout.push_back(rm[ 9]);    //CH0RSTR
	  23'h0a:  	dout.push_back(rm[10]);    //CH1RSTR
	  23'h0b:  	dout.push_back(rm[11]);    //CH2RSTR
	  23'h0c:  	dout.push_back(rm[12]);    //CH3RSTR
	  23'h0d:  	dout.push_back(rm[13]);    //DBGCFGR
	  23'h0e:  	dout.push_back(0);
	  23'h10:  	begin                      //MISR
			  dout.push_back(rm[16]);      
			  irisr_clr = 1'b1;
			end
	  23'h11:  	dout.push_back(0);
	endcase
//	$display("dout:%h",dout[$]);

	@(posedge wif.clk);
	  irisr_clr = 1'b0;

endtask:  reg_read


task sys_refmodel::rst_check(bit[31:0] rst_time,int i);
    int cnt=0;

	//delay caused by decoder
	@(posedge wif.clk);
        
	cnt = rst_time; 
	//$display("%h",addr);
	//$display("rst_time:%h",cnt);
	while(cnt>0) begin
	  @(posedge wif.clk);
	  if(vif.soft_rstn[i])
	    break;
	  cnt--;
	end

	@(negedge wif.clk);
	if(cnt!=0 | !vif.soft_rstn[i]) begin
	  rst_error[i]++;
	  $display("\nScoreBoard(ERROR):  rst_time_error\t@%t",$realtime);
	  case(i)
	    0:	$display("rst_module:\tSYS");
	    1:	$display("rst_module:\tch0");
	    2:	$display("rst_module:\tch1");
	    3:	$display("rst_module:\tch2");
	    4:	$display("rst_module:\tch3");
	  endcase
	  $display("cnt:\t%d",cnt);
	  $display("soft_rstn:\t%b",vif.soft_rstn[i]);
	end

endtask: rst_check



task sys_refmodel::output_trace(bit[24:0] addr);
  if(addr[24:20] == 5'h0);
  begin
  sysreg_trans  tr_temp;
  bit		irq = |rm[14];

  	//delay caused by decoder
  	@(posedge wif.clk);
  	@(negedge wif.clk);
	tr_temp = new();
        tr_temp.dbg_enable   = rm[13][0:0];    //DBGCFGR
        tr_temp.dbg_data_sel = rm[13][1:1];
        tr_temp.dbg_ch_sel   = rm[13][3:2];
        tr_temp.irq	         = irq;
	sysout.push_back(tr_temp);
  end
  // $display("addr:%0h",addr);

  //$display("rm:%h",rm[addr[24: 2]]);
  //$display("din:%h",din);

endtask:  output_trace