用Verilog验证单端口RAM

Question

我为一个端口SRAM编写了一个Verilog测试平台，在地址i上进行写操作，并在i-1地址连续读取它。如下所示

task write_read;
integer i;
begin
 for (i=1,i<=20,i=i+1) begin
  write_mode(i,$urandom);  // i= address, $urandom=data
  read_mode(i-1);  //i-1 address
 end
end
endtask

PS: write_mode、read_mode是设置wen、cs和一些扫描模式引脚以及延迟的任务。

在Verdi波形中，我看到了正确的读写操作。但是，我想验证写入地址的数据与从日志文件读取的地址上的数据相同。如果它们不匹配，则应该显示错误。我不知道如何在代码中实现这一点。当我有数百个编译器时，我无法进入所有的编译器路径，打开它们的波形文件并手动检查读、写操作。

我试图存储特定地址位置的$urandom数据，但每次迭代周期都会覆盖它。我可以使用一个函数来返回$urandom值，但是我的环境包含延迟，所以我不能使用函数。

简单地说，我正在寻找Verilog代码帮助，在没有转储波形的情况下进行内存验证。，能帮上忙吗？如果需要更多的细节，请告诉我

谢谢

Answer 1

使用Kristen框架，您可以获得一些可重用的测试工作台代码。下面是那个测试平台上的一个名为test_support.vh的文件。该文件包含用于显示错误和计数错误的函数。我建议您在比较内存位置时使用===或!==，因为未定义的信号可能在不经意间匹配。在测试结束时，调用display_test_final_status，这将在日志文件中为您创建一个总体测试报告。在完全回归完成后，您现在可以在日志文件上运行grep，查找错误，它将显示一致的mannor中的任何失败。

我有一个非常喜欢的Perl回归脚本，它运行我所有的测试，自动完成grep，并发送一封成功或失败的电子邮件。

在每个测试的基础上，您将需要设置一些定义来指示测试名称，以及是否希望错误立即停止测试。

祝好运。

// -----------------------------------------------------------
// test_support.vh                                         
// Generated file specifies which numerical test cases to run.                 
// Kristen Software License - Version 1.0 - January 1st, 2019                  
//                                                                             
// Permission is hereby granted, free of charge, to any person or organization 
// obtaining a copy of the software and accompanying documentation covered by  
// this license (the "Software") to use, reproduce, display, distribute,     
// execute, and transmit the Software, and to prepare derivative works of the  
// Software, and to permit third-parties to whom the Software is furnished to  
// do so, all subject to the following:                                        
//                                                                             
// The copyright notices in the Software and this entire statement, including  
// the above license grant, this restriction and the following disclaimer,     
// must be included in all copies of the Software, in whole or in part, and    
// all derivative works of the Software, unless such copies or derivative      
// works are solely in the form of machine-executable object code generated by 
// a source language processor.                                                
//                                                                             
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,    
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT   
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE   
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, 
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.                                                   
                                                                               
// GENERATED FILE - DO NOT MODIFY THIS FILE MANUALLY.                          
// -----------------------------------------------------------

logic[63:0] error_count = 0;
logic[63:0] lcl_error_count = 0;
logic bool_quick_mode = 0;
logic[511:0] support_test_passes;
logic[15:0] support_test_fails [0:511];
logic[511:0] support_test_was_run;
task test_init;
error_count = 0;     
lcl_error_count = 0; 
endtask

task display_test_begin_status;
    begin 
        
        `ifdef QUICK_MODE
        bool_quick_mode = 1;
        `endif

        $display("=========================================================================");
        $display("| Test: %s    QUICK_MODE = %s", `TEST_NAME_STR, bool_quick_mode ? "ON" : "OFF");
        $display("| VERBOSE = %0d", `VERBOSE);
        $display("=========================================================================");
    end
endtask

task display_test_start;
    input[31:0] test_id;
    input string test_description;

    begin
        lcl_error_count = 0;
        $display("=========================================================================");
        $display("%0t: Test %0d : %s.", $time, test_id, test_description);
        $display("=========================================================================");
    end
endtask

task display_test_end;
    input[31:0] test_id;
    begin
        $display("=========================================================================");
        $display("%0t: Test %0d Complete with %0d ERRORS.", $time, test_id, lcl_error_count);
        $display("=========================================================================");
        support_test_was_run[test_id] = 1'b1;
        if (lcl_error_count == 0) 
            support_test_passes[test_id] = 1'b1;
        else
            support_test_fails[test_id] = lcl_error_count;
    end
endtask

task display_error_inc;
    input string error_description;
    begin
       error_count++;
       lcl_error_count++;
       //$display("=========================================================================");
       $display("%0t: ERROR:  %s : error_count: %0d",$time, error_description, error_count );
       //$display("=========================================================================");
       `ifdef TEST_STOP_ON_ERROR
        if (error_count >= `TEST_STOP_ON_ERROR_LIMIT) begin
            $display("%0t, Stopping on error count = %d, %m", $time, error_count); 
            $finish();
        end
       `endif
    end
endtask

task display_test_final_status;
    //input string testname;
    begin
       $display("=========================================================================");
       $display("%0t: Test %s %s with %0d ERRORS",$time, `TEST_NAME_STR, error_count > 0 ? "FAILS" : "PASSES",error_count);
       $display("=========================================================================");
       if (error_count !== 'h0)
           begin
              $display("Test failures:");
              for (int err_fail_cnt = 0;err_fail_cnt < 512; err_fail_cnt = err_fail_cnt + 1)
                  begin
                      if (support_test_was_run[err_fail_cnt] == 1'b1 && support_test_passes[err_fail_cnt] != 1'b1)
                          begin
                             $display("Test %d, fails with %d errors", err_fail_cnt, support_test_fails[err_fail_cnt]);
                          end
                  end
           end
    end
endtask

task display_no_test_found;
    input[31:0] test_id;
    input string test_description;

    begin
        lcl_error_count = 0;
        $display("=========================================================================");
        $display("%0t: Test %0d : %s NOT FOUND SKIPPING.", $time, test_id, test_description);
        $display("=========================================================================");
    end
endtask

在Kristen生成的测试平台上，当检测到RAM单元时，这就是正在运行的测试。我认为这是一种算法解决方案，因为您必须生成几个向量字符串和其他函数，将这些字符串转换为地址。

xreg_v1___write_mpi_test是写入RAM的任务，xreg_v1___read_mpi_test是从RAM读取的任务。有一个比较任务xreg_v1___register_compare_with_error，它显然会生成一个错误。我也会在下面展示这些。

    // This is a casex snippet from the RAM test
   7'd2: begin
         // xreg_v1_0_0_mem_ack test
         $display("%0t, xreg_v1_0_0_mem_ack test", $time);
         oo_limit = get_entries_by_index(tc_index) > 256 ? 256 : get_entries_by_index(tc_index);  //Max number of entries for this test
         mm_step  = get_entry_offset(tc_index);
         nn_limit = perfect_by_datawidth(get_size_by_index(get_address_by_index(tc_index)),DATAPATH_WIDTH)/8; // Number of bytes for this entry
         nn_step = DATAPATH_WIDTH == 8  ? 1 : DATAPATH_WIDTH == 16 ? 2 : DATAPATH_WIDTH == 32 ? 4 : 8;
         for(oo = 0; oo < oo_limit; oo = oo + 1) // Move through each entry we will be testing
         begin
            for (nn = 0; nn < nn_limit; nn = nn + nn_step) // Walk through each access of a given entry
            begin
            test_address = get_address_by_index(tc_index) + (oo*mm_step) + nn;
            expected = oo[7:0] ^ nn[7:0] ^ mm_step[7:0] ^ nn_step[7:0]; 
        expected = {expected[6:0],expected[7],expected[2:0],expected[7:3],expected[5],expected[3],expected[1],expected[7],expected[0],expected[2],expected[6],expected[4],expected[7:0]};
            xreg_v1_0_0_write_mpi_test(aclk, test_address, expected);
            end
         end
         for(oo = 0; oo < oo_limit; oo = oo + 1) // Move through each entry we will be testing
         begin
            for (nn = 0; nn < nn_limit; nn = nn + nn_step) // Walk through each access of a given entry
            begin
            test_address = get_address_by_index(tc_index) + (oo*mm_step) + nn;
        mask = get_entry_mask_by_index(tc_index);
            expected = oo[7:0] ^ nn[7:0] ^ mm_step[7:0] ^ nn_step[7:0]; 
        expected = {expected[6:0],expected[7],expected[2:0],expected[7:3],expected[5],expected[3],expected[1],expected[7],expected[0],expected[2],expected[6],expected[4],expected[7:0]} & (get_entry_mask_by_index(tc_index) >> (nn*8));
            xreg_v1_0_0_read_mpi_test(aclk, test_address, result);
            xreg_v1_0_0_register_compare_with_error(test_address,expected,result);
            end
         end
    end

下面是一些引用的任务，显示写入、读取和比较已实现的内容。我认为其中一些是系统Verilog，所以你必须把它当作算法来处理。

task automatic xreg_v1_0_0_read_mpi_test;
    ref logic clock;
    input  [`TEST_ADDR_WIDTH-1:0] address;
    output [`TEST_DATA_WIDTH-1:0] result;
    begin
        $display("ENTER >>> xreg_v1_0_0_read_mpi_test");
        repeat(1) @(posedge clock);
        `TEST_MPI_ADDR = address;
        `TEST_MPI_RD_REQ = 1'b1;
        `TEST_MPI_ENABLE = 1'b1;
        while (!`TEST_MPI_ACK) repeat(1) @(posedge clock);
        `TEST_MPI_ADDR = 'h0;
        `TEST_MPI_RD_REQ = 1'b0;
        `TEST_MPI_ENABLE = 1'b0;
        result = `TEST_MPI_RD_DATA;
        $display("WAITING ACK <<< xreg_v1_0_0_read_mpi_test");
        while (`TEST_MPI_ACK) repeat(1) @(posedge clock);
        $display("EXIT <<< xreg_v1_0_0_read_mpi_test");
    end
endtask

task automatic xreg_v1_0_0_write_mpi_test;
    ref logic clock;
    input  [`TEST_ADDR_WIDTH-1:0] address;
    input [`TEST_DATA_WIDTH-1:0]  data;
    begin
        $display("ENTER >>> xreg_v1_0_0_write_mpi_test");
        repeat(1) @(posedge clock);
        `TEST_MPI_ADDR = address;
        `TEST_MPI_WR_DATA = data;
        `TEST_MPI_WR_REQ = 1'b1;
        `TEST_MPI_ENABLE = 1'b1;
        while (!`TEST_MPI_ACK) repeat(1) @(posedge clock);
        `TEST_MPI_ADDR = 'h0;
        `TEST_MPI_WR_DATA = 'h0;
        `TEST_MPI_WR_REQ = 1'b0;
        `TEST_MPI_ENABLE = 1'b0;
        $display("WAITING ACK <<< xreg_v1_0_0_write_mpi_test");
        while (`TEST_MPI_ACK) repeat(1) @(posedge clock);
        $display("EXIT <<< xreg_v1_0_0_write_mpi_test");
    end
endtask

task automatic xreg_v1_0_0_register_compare_with_error;
    input [`TEST_ADDR_WIDTH-1:0] address;
    input [`TEST_DATA_WIDTH-1:0] expected;
    input [`TEST_DATA_WIDTH-1:0] result;
    begin
        $display("ENTER >>> xreg_v1_0_0_register_compare_with_error");
        if (expected !== result)
            begin 
            $display("%0t, Address = 0x%X", $time, address);
            $display("%0t, Expected 0x%X", $time, expected);
            $display("%0t, Read     0x%X", $time, result);
            display_error_inc("xreg_v1_0_0_rdconst_test: Mismatch between read and expected data.");
            end
        $display("EXIT <<< xreg_v1_0_0_register_compare_with_error");
    end
endtask

Answer 2

首先要将写入数据存储在队列中。然后，在读取SRAM时，将地址传递给队列，并比较queue_data_out和sram_data_out。如果比较失败，则打印错误。见下面的伪代码。

task write_read;
integer i;
bit write_data_queue [$];
begin
 for (i=1,i<=20,i=i+1) begin
  write_mode(i,$urandom);  // i= address, $urandom=data

  write_data_queue.push_front($urandom);

  read_mode(i-1);  //i-1 address

  queue_data = write_data_queue.pop_front();

  if(queue_data != read_mode(i-1))
   $display("ERROR'\n")

 end
end
endtask