302 lines
9.9 KiB
Coq
302 lines
9.9 KiB
Coq
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`begin_keywords "1364-2005"
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//
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// Copyright (c) 1999 Thomas Coonan (tcoonan@mindspring.com)
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//
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// This source code is free software; you can redistribute it
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// and/or modify it in source code form under the terms of the GNU
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// General Public License as published by the Free Software
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// Foundation; either version 2 of the License, or (at your option)
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// any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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//
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//
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// Behavioral Verilog for CRC16 and CRC32 for use in a testbench.
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//
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// The specific polynomials and conventions regarding bit-ordering etc.
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// are specific to the Cable Modem DOCSIS protocol, but the general scheme
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// should be reusable for other types of CRCs with some fiddling.
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//
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// This CRC code works for a specific type of network protocol, and it
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// must do certain byte swappings, etc. You may need to play with it
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// for your protocol. Also, make sure the polynomials are what you
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// really want. This is obviously, not synthesizable - I just used this
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// in a testbench at one point.
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//
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// These tasks are crude and rely on some global parameters. They should
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// also read from a file, yada yada yada. It is probably better to do this
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// with a PLI call, but here it is anyway..
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//
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// The test case includes a golden DOCSIS (Cable Modem) test message that
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// was captured in a lab.
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//
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// tom coonan, 1999.
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//
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module test_gencrc;
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// *** Buffer for the Golden Message ***
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reg [7:0] test_packet[0:54];
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// *** Global parameter block for the CRC32 calculator.
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//
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parameter CRC32_POLY = 32'h04C11DB7;
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reg [ 7:0] crc32_packet[0:255];
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integer crc32_length;
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reg [31:0] crc32_result;
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// *** Global parameter block for the CRC16 calculator.
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//
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parameter CRC16_POLY = 16'h1020;
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reg [ 7:0] crc16_packet[0:255];
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integer crc16_length;
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reg [15:0] crc16_result;
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`define TEST_GENCRC
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`ifdef TEST_GENCRC
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// Call the main test task and then quit.
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//
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initial begin
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main_test;
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$finish;
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end
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`endif
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// ****************************************************************
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// *
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// * GOLDEN MESSAGE
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// *
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// * The golden message is a DOCSIS frame that was captured off
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// * the Broadcom reference design. It is a MAP message. It
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// * includes a HCS (crc 16) and a CRC32.
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// *
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// *
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// ****************************************************************
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//
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task initialize_test_packet;
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begin
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test_packet[00] = 8'hC2; // FC. HCS coverage starts here.
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test_packet[01] = 8'h00; // MACPARAM
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test_packet[02] = 8'h00; // MAC LEN
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test_packet[03] = 8'h30; // MAC LEN. HCS Coverage includes this byte and ends here.
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test_packet[04] = 8'hF2; // CRC16 (also known as HCS)
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test_packet[05] = 8'hCF; // CRC16 cont..
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test_packet[06] = 8'h01; // Start of the IEEE payload. CRC32 covererage starts here. This is the DA field
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test_packet[07] = 8'hE0; // DA field cont..
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test_packet[08] = 8'h2F; // DA field cont..
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test_packet[09] = 8'h00; // DA field cont..
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test_packet[10] = 8'h00; // DA field cont..
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test_packet[11] = 8'h01; // DA field cont..
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test_packet[12] = 8'h00; // SA field
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test_packet[13] = 8'h80; // SA field cont..
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test_packet[14] = 8'h42; // SA field cont..
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test_packet[15] = 8'h42; // SA field cont..
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test_packet[16] = 8'h20; // SA field cont..
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test_packet[17] = 8'h9E; // SA field cont..
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test_packet[18] = 8'h00; // IEEE LEN field
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test_packet[19] = 8'h1E; // IEEE LEN field cont.
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test_packet[20] = 8'h00; // LLC field.
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test_packet[21] = 8'h00; // LLC field cont...
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test_packet[22] = 8'h03; // LLC field cont...
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test_packet[23] = 8'h01; // LLC field cont...
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test_packet[24] = 8'h03; // LLC field cont... This is also the TYPE, which indicates MAP.
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test_packet[25] = 8'h00; // LLC field cont...
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test_packet[26] = 8'h01; // Start of MAP message payload.
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test_packet[27] = 8'h01; // MAP message payload..
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test_packet[28] = 8'h02; // MAP message payload..
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test_packet[29] = 8'h00; // MAP message payload..
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test_packet[30] = 8'h00; // MAP message payload..
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test_packet[31] = 8'h18; // MAP message payload..
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test_packet[32] = 8'hAA; // MAP message payload..
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test_packet[33] = 8'h58; // MAP message payload..
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test_packet[34] = 8'h00; // MAP message payload..
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test_packet[35] = 8'h18; // MAP message payload..
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test_packet[36] = 8'hA8; // MAP message payload..
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test_packet[37] = 8'hA0; // MAP message payload..
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test_packet[38] = 8'h02; // MAP message payload..
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test_packet[39] = 8'h03; // MAP message payload..
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test_packet[40] = 8'h03; // MAP message payload..
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test_packet[41] = 8'h08; // MAP message payload..
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test_packet[42] = 8'hFF; // MAP message payload..
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test_packet[43] = 8'hFC; // MAP message payload..
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test_packet[44] = 8'h40; // MAP message payload..
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test_packet[45] = 8'h00; // MAP message payload..
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test_packet[46] = 8'h00; // MAP message payload..
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test_packet[47] = 8'h01; // MAP message payload..
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test_packet[48] = 8'hC0; // MAP message payload..
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test_packet[49] = 8'h14; // Last byte of MAP payload, last byte covered by CRC32.
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test_packet[50] = 8'hDD; // CRC32 Starts here
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test_packet[51] = 8'hBF; // CRC32 cont..
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test_packet[52] = 8'hC1; // CRC32 cont..
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test_packet[53] = 8'h2E; // Last byte of CRC32, last byte of DOCSIS.
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end
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endtask
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// *************************************************************************
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// *
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// * Main test task.
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// *
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// * Use our primary "golden packet". Copy into the generic global
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// * variables that the low-level 'gencrc16' and 'gencrc32' tasks use.
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// * Comare against the expected values and report SUCCESS or FAILURE.
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// *
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// *************************************************************************
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//
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task main_test;
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integer i, j;
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integer num_errors;
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reg [15:0] crc16_expected;
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reg [31:0] crc32_expected;
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begin
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num_errors = 0;
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// Initialize the Golden Message!
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//
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initialize_test_packet;
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// **** TEST CRC16
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//
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//
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// Copy golden test_packet into the main crc16 buffer..
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for (i=0; i<4; i=i+1) begin
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crc16_packet[i] = test_packet[i];
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end
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crc16_expected = {test_packet[4], test_packet[5]};
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crc16_length = 4; // Must tell test function the length
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gencrc16; // Call main test function
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if (crc16_result !== crc16_expected)
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begin
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num_errors = num_errors + 1;
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$display ("FAILED - Actual crc16_result = %h, Expected = %h",
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crc16_result, crc16_expected);
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end
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// **** TEST CRC16
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//
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j = 0;
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for (i=6; i<50; i=i+1) begin
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crc32_packet[j] = test_packet[i];
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j = j + 1;
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end
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crc32_expected = {test_packet[50], test_packet[51], test_packet[52], test_packet[53]};
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crc32_length = 44;
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gencrc32;
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if (crc32_result !== crc32_expected)
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begin
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$display ("FAILED - Actual crc32_result = %h, Expected = %h",
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crc32_result, crc32_expected);
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num_errors = num_errors + 1;
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end
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if(num_errors == 0)
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$display("PASSED");
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end
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endtask
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// ****************************************************************
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// *
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// * Main working CRC tasks are: gencrc16, gencrc32.
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// *
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// * These tasks rely on some globals (see front of program).
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// *
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// ****************************************************************
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// Generate a (DOCSIS) CRC16.
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//
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// Uses the GLOBAL variables:
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//
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// Globals referenced:
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// parameter CRC16_POLY = 16'h1020;
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// reg [ 7:0] crc16_packet[0:255];
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// integer crc16_length;
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//
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// Globals modified:
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// reg [15:0] crc16_result;
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//
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task gencrc16;
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integer byte, bit;
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reg msb;
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reg [7:0] current_byte;
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reg [15:0] temp;
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begin
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crc16_result = 16'hffff;
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for (byte = 0; byte < crc16_length; byte = byte + 1) begin
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current_byte = crc16_packet[byte];
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for (bit = 0; bit < 8; bit = bit + 1) begin
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msb = crc16_result[15];
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crc16_result = crc16_result << 1;
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if (msb != current_byte[bit]) begin
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crc16_result = crc16_result ^ CRC16_POLY;
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crc16_result[0] = 1;
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end
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end
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end
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// Last step is to "mirror" every bit, swap the 2 bytes, and then complement each bit.
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//
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// Mirror:
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for (bit = 0; bit < 16; bit = bit + 1)
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temp[15-bit] = crc16_result[bit];
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// Swap and Complement:
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crc16_result = ~{temp[7:0], temp[15:8]};
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end
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endtask
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// Generate a (DOCSIS) CRC32.
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//
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// Uses the GLOBAL variables:
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//
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// Globals referenced:
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// parameter CRC32_POLY = 32'h04C11DB7;
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// reg [ 7:0] crc32_packet[0:255];
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// integer crc32_length;
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//
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// Globals modified:
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// reg [31:0] crc32_result;
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//
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task gencrc32;
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integer byte, bit;
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reg msb;
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reg [7:0] current_byte;
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reg [31:0] temp;
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begin
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crc32_result = 32'hffffffff;
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for (byte = 0; byte < crc32_length; byte = byte + 1) begin
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current_byte = crc32_packet[byte];
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for (bit = 0; bit < 8; bit = bit + 1) begin
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msb = crc32_result[31];
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crc32_result = crc32_result << 1;
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if (msb != current_byte[bit]) begin
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crc32_result = crc32_result ^ CRC32_POLY;
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crc32_result[0] = 1;
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end
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end
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end
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// Last step is to "mirror" every bit, swap the 4 bytes, and then complement each bit.
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//
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// Mirror:
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for (bit = 0; bit < 32; bit = bit + 1)
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temp[31-bit] = crc32_result[bit];
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// Swap and Complement:
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crc32_result = ~{temp[7:0], temp[15:8], temp[23:16], temp[31:24]};
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end
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endtask
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endmodule
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`end_keywords
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