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import std_defs::*;
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import std_defs::*;
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interface uart_if ();
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interface uart_if ();
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logic txd = 0; //from testbench driver
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logic txd = 0; //from testbench driver
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logic rxd = 0; //to testbench monitor
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logic rxd; //to testbench monitor
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endinterface : uart_if
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endinterface : uart_if
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typedef logic[11:0] cpu_addr_t;
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typedef logic[11:0] cpu_addr_t;
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typedef logic[7:0] cpu_data_t;
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typedef logic[7:0] cpu_data_t;
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forever begin
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forever begin
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mbx.get( data ); //block if no transactions waiting.
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mbx.get( data ); //block if no transactions waiting.
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data_bits = data;
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data_bits = data;
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//start bit
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//start bit
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uart_.txd = 0;
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uart_.txd = 0;
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#(1/baud_rate)s;
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#(1s/baud_rate);
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//8 bits of data
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//8 bits of data
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for(uint8 i=0; i<8; i++) begin
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for(uint8 i=0; i<8; i++) begin
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uart_.txd = data_bits[i]; //least significant bit first.
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uart_.txd = data_bits[i]; //least significant bit first.
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#(1/baud_rate)s;
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#(1s/baud_rate);
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end
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end
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//1 stop bit
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//1 stop bit
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uart_.txd = 1;
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uart_.txd = 1;
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#(1/baud_rate)s;
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#(1s/baud_rate);
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end
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end
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end
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end
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join_none
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join_none
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endtask
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endtask
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endclass
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endclass
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task automatic run();
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task automatic run();
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fork begin
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fork begin
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forever begin
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forever begin
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//Look for a valid start bit. Must be at least 1/2 bit period duration.
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//Look for a valid start bit. Must be at least 1/2 bit period duration.
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@(negedge uart_.rxd);
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@(negedge uart_.rxd);
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#(0.5 * 1/baud_rate)s;
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#(0.5 * 1s/baud_rate);
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if ( uart_.rxd == 0 ) begin
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if ( uart_.rxd == 0 ) begin
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logic[7:0] data_bits;
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logic[7:0] data_bits;
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//read in 8 data bits, LSBit first, sampling in the center of the bit period.
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//read in 8 data bits, LSBit first, sampling in the center of the bit period.
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for(uint8 i=0; i<8; i++) begin
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for(uint8 i=0; i<8; i++) begin
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#( 1/baud_rate )s;
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#(1s/baud_rate);
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data_bits[i] = uart_.rxd;
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data_bits[i] = uart_.rxd;
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end
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end
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//check stop bit.
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//check stop bit.
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#( 1/baud_rate )s;
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#(1s/baud_rate);
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if ( uart_.rxd != 1 ) begin
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if ( uart_.rxd != 1 ) begin
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$display("Monitor: Invalid stop bit.");
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$display("Monitor: Invalid stop bit.");
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end
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end
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else begin
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else begin
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//valid stop bit so generate transaction.
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//valid stop bit so generate transaction.
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//ok, now run some tests.
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//ok, now run some tests.
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test_cpu_interface();
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test_cpu_interface();
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test_serial_facing_loopback(); //This one is also a good test for the testbench UART monitor/driver classes.
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test_serial_facing_loopback(); //This one is also a good test for the testbench UART monitor/driver classes.
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test_cpu_to_txd();
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test_cpu_to_txd();
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test_rxd_to_cpu();
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//test_rxd_to_cpu();
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$display("%m: %t << Simulation ran to completion >>", $time);
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$display("%m: %t << Simulation ran to completion >>", $time);
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// $stop(0); //stop the simulation
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// $stop(0); //stop the simulation
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end
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end
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uart_driver_mbx.put( data );
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uart_driver_mbx.put( data );
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sent_data_mbx.put( data );
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sent_data_mbx.put( data );
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end
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end
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//Gives some time for any remaining transactions to propagate through the DUT.
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//Gives some time for any remaining transactions to propagate through the DUT.
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#( `UART_FIFO_SIZE * (12 * 1/`BAUD_RATE))s; //10 bits/ baud, but allow for 12.
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#( `UART_FIFO_SIZE * (12 * 1s/`BAUD_RATE)); //10 bits/ baud, but allow for 12.
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//Check the sent data comes back error free.
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//Check the sent data comes back error free.
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compare_mailbox_data( sent_data_mbx, uart_monitor_mbx );
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compare_mailbox_data( sent_data_mbx, uart_monitor_mbx );
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endtask
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endtask
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sent_data_mbx.put(data);
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sent_data_mbx.put(data);
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end
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end
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end
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end
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//Gives some time for any remaining transactions to propagate through the DUT.
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//Gives some time for any remaining transactions to propagate through the DUT.
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#( `UART_FIFO_SIZE * (12 * 1/`BAUD_RATE))s; //10 bits/ baud, but allow for 12.
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#( `UART_FIFO_SIZE * (12 * 1s/`BAUD_RATE)); //10 bits/ baud, but allow for 12.
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//Check the sent and received data is the same.
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//Check the sent and received data is the same.
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compare_mailbox_data( sent_data_mbx, uart_monitor_mbx );
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compare_mailbox_data( sent_data_mbx, uart_monitor_mbx );
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endtask
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endtask
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//Check all reference mailbox items against dut mailbox items. Expected to be identical, report differences.
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//Check all reference mailbox items against dut mailbox items. Expected to be identical, report differences.
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function automatic void compare_mailbox_data( mailbox #(uint8) ref_mbx, mailbox #(uint8) dut_mbx );
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function automatic void compare_mailbox_data( mailbox #(uint8) ref_mbx, mailbox #(uint8) dut_mbx );
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uint32 error = 0;
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uint32 error = 0;
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uint32 good = 0;
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uint32 good = 0;
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repeat( ref_mbx.size() ) begin
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uint32 ref_mbx_num;
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uint32 dut_mbx_num;
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ref_mbx_num = ref_mbx.num();
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dut_mbx_num = dut_mbx.num();
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repeat( ref_mbx_num ) begin
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uint8 dut_data;
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uint8 dut_data;
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uint8 ref_data;
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uint8 ref_data;
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uint32 tryget_result;
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uint32 tryget_result;
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ref_mbx.get( ref_data );
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ref_mbx.try_get( ref_data );
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//try to get dut data, may not be there if dut swallowed it.
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//try to get dut data, may not be there if dut swallowed it.
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tryget_result = dut_mbx.try_get( dut_data );
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tryget_result = dut_mbx.try_get( dut_data );
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if (tryget_result) begin
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if (tryget_result) begin
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if (ref_data != dut_data) begin
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if (ref_data != dut_data) begin
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error++;
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error++;
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Line 351... |
end
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end
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break; //no more DUT data
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break; //no more DUT data
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end
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end
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end
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end
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$display("Good: %2d, Errored: %2d, Excess reference %2d, Excess DUT %2d",
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$display("Good: %2d, Errored: %2d, Excess reference %2d, Excess DUT %2d",
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good, error, ref_mbx.size(), dut_mbx.size());
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good, error, ref_mbx_num, dut_mbx_num);
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endfunction
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endfunction
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endmodule
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endmodule
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