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module env_io (/*AUTOARG*/
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module env_io (/*AUTOARG*/
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// Outputs
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// Outputs
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DI,
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DI,
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// Inputs
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// Inputs
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clk, iorq_n, rd_n, wr_n, addr, DO
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clk, iorq_n, rd_n, wr_n, addr, DO
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);
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);
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parameter str_buf_sz = 256;
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parameter str_buf_sz = 256;
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input clk;
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input clk;
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input iorq_n;
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input iorq_n;
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input rd_n;
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input rd_n;
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input wr_n;
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input wr_n;
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input [7:0] addr;
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input [7:0] addr;
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input [7:0] DO;
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input [7:0] DO;
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inout [7:0] DI;
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inout [7:0] DI;
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reg [7:0] io_data;
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reg [7:0] io_data;
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reg [7:0] str_buf [0:str_buf_sz-1];
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reg [7:0] str_buf [0:str_buf_sz-1];
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reg io_cs;
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reg io_cs;
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integer buf_ptr, i;
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integer buf_ptr, i;
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reg [7:0] timeout_ctl;
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reg [7:0] timeout_ctl;
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reg [15:0] cur_timeout;
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reg [15:0] cur_timeout;
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reg [15:0] max_timeout;
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reg [15:0] max_timeout;
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reg [7:0] int_countdown;
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reg [7:0] int_countdown;
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assign DI = (!iorq_n & !rd_n & io_cs) ? io_data : {8{1'bz}};
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assign DI = (!iorq_n & !rd_n & io_cs) ? io_data : {8{1'bz}};
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initial
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initial
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begin
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begin
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io_cs = 0;
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io_cs = 0;
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buf_ptr = 0;
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buf_ptr = 0;
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cur_timeout = 0;
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cur_timeout = 0;
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max_timeout = 10000;
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max_timeout = 10000;
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timeout_ctl = 1;
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timeout_ctl = 1;
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int_countdown = 0;
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int_countdown = 0;
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end
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end
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always @(posedge clk)
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always @(posedge clk)
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begin
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begin
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if (!iorq_n & !wr_n)
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if (!iorq_n & !wr_n)
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case (addr)
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case (addr)
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8'h80 :
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8'h80 :
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begin
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begin
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case (DO)
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case (DO)
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1 : tb_top.test_pass;
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1 : tb_top.test_pass;
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2 : tb_top.test_fail;
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2 : tb_top.test_fail;
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3 : tb_top.dumpon;
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3 : tb_top.dumpon;
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4 : tb_top.dumpoff;
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4 : tb_top.dumpoff;
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default :
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default :
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begin
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begin
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$display ("%t: ERROR : Unknown I/O command %x", $time, DO);
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$display ("%t: ERROR : Unknown I/O command %x", $time, DO);
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end
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end
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endcase // case(DO)
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endcase // case(DO)
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end // case: :...
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end // case: :...
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8'h81 :
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8'h81 :
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begin
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begin
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str_buf[buf_ptr] = DO;
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str_buf[buf_ptr] = DO;
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buf_ptr = buf_ptr + 1;
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buf_ptr = buf_ptr + 1;
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if (buf_ptr == str_buf_sz)
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if (buf_ptr == str_buf_sz)
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begin
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begin
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$display ("%t: WARNING : String buffer reached maximum size without detecting EOL", $time);
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$display ("%t: WARNING : String buffer reached maximum size without detecting EOL", $time);
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$write ("%t: WARNING : Contents: ", $time);
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$write ("%t: WARNING : Contents: ", $time);
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for (i=0; i<buf_ptr; i=i+1)
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for (i=0; i<buf_ptr; i=i+1)
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$write ("%s", str_buf[i]);
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$write ("%s", str_buf[i]);
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$write ("\n");
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$write ("\n");
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buf_ptr = 0;
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buf_ptr = 0;
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end
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end
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//$display ("%t: DEBUG : Detected write of character %x", $time, DO);
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//$display ("%t: DEBUG : Detected write of character %x", $time, DO);
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if (DO == 8'h0A)
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if (DO == 8'h0A)
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begin
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begin
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$write ("%t: PROGRAM : ", $time);
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$write ("%t: PROGRAM : ", $time);
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for (i=0; i<buf_ptr; i=i+1)
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for (i=0; i<buf_ptr; i=i+1)
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$write ("%s", str_buf[i]);
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$write ("%s", str_buf[i]);
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buf_ptr = 0;
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buf_ptr = 0;
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end
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end
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end // case: 8'h81
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end // case: 8'h81
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8'h82 :
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8'h82 :
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begin
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begin
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timeout_ctl = DO;
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timeout_ctl = DO;
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end
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end
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8'h83 : max_timeout[7:0] = DO;
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8'h83 : max_timeout[7:0] = DO;
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8'h84 : max_timeout[15:8] = DO;
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8'h84 : max_timeout[15:8] = DO;
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8'h90 : int_countdown = DO;
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8'h90 : int_countdown = DO;
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endcase // case(addr)
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endcase // case(addr)
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end // always @ (posedge clk)
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end // always @ (posedge clk)
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always @(posedge clk)
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always @(posedge clk)
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begin
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begin
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if (timeout_ctl[1])
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if (timeout_ctl[1])
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cur_timeout = 0;
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cur_timeout = 0;
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else if (timeout_ctl[0])
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else if (timeout_ctl[0])
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cur_timeout = cur_timeout + 1;
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cur_timeout = cur_timeout + 1;
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if (cur_timeout >= max_timeout)
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if (cur_timeout >= max_timeout)
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begin
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begin
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$display ("%t: ERROR : Reached timeout %d cycles", $time, max_timeout);
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$display ("%t: ERROR : Reached timeout %d cycles", $time, max_timeout);
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tb_top.test_fail;
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tb_top.test_fail;
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end
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end
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end // always @ (posedge clk)
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end // always @ (posedge clk)
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always @(posedge clk)
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always @(posedge clk)
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begin
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begin
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if (int_countdown == 1)
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if (int_countdown == 1)
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begin
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begin
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tb_top.int_n <= #1 1'b0;
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tb_top.int_n <= #1 1'b0;
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int_countdown = 0;
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int_countdown = 0;
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end
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end
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else if (int_countdown > 1)
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else if (int_countdown > 1)
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int_countdown = int_countdown - 1;
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int_countdown = int_countdown - 1;
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end
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end
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endmodule // env_io
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endmodule // env_io
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