// Copyright 2009 Altera Corporation. All rights reserved. // Altera products are protected under numerous U.S. and foreign patents, // maskwork rights, copyrights and other intellectual property laws. // // This reference design file, and your use thereof, is subject to and governed // by the terms and conditions of the applicable Altera Reference Design // License Agreement (either as signed by you or found at www.altera.com). By // using this reference design file, you indicate your acceptance of such terms // and conditions between you and Altera Corporation. In the event that you do // not agree with such terms and conditions, you may not use the reference // design file and please promptly destroy any copies you have made. // // This reference design file is being provided on an "as-is" basis and as an // accommodation and therefore all warranties, representations or guarantees of // any kind (whether express, implied or statutory) including, without // limitation, warranties of merchantability, non-infringement, or fitness for // a particular purpose, are specifically disclaimed. By making this reference // design file available, Altera expressly does not recommend, suggest or // require that this reference design file be used in combination with any // other product not provided by Altera. ///////////////////////////////////////////////////////////////////////////// // // 32 bit CRC of 21 data bits (forward - LSB first) // polynomial : 00a00805 // x^23 + x^21 + x^11 + x^2 + x^0 // // CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC DDDDDDDDDDDDDDDDDDDDD // 00000000001111111111222222222233 000000000011111111112 // 01234567890123456789012345678901 012345678901234567890 // C00 = ...........#........#.#......#.. ..................... // C01 = ............#........#.#......#. ..................... // C02 = ...........#.#......#...#....#.# ..................... // C03 = ............#.#......#...#....#. ..................... // C04 = .............#.#......#...#....# ..................... // C05 = ..............#.#......#...#.... ..................... // C06 = ...............#.#......#...#... ..................... // C07 = ................#.#......#...#.. ..................... // C08 = .................#.#......#...#. ..................... // C09 = ..................#.#......#...# ..................... // C10 = ...................#.#......#... ..................... // C11 = ...........#.................... ..................... // C12 = ............#................... ..................... // C13 = .............#.................. ..................... // C14 = ..............#................. ..................... // C15 = ...............#................ ..................... // C16 = ................#............... ..................... // C17 = .................#.............. ..................... // C18 = ..................#............. ..................... // C19 = ...................#............ ..................... // C20 = ....................#........... ..................... // C21 = #..........#........###......#.. ..................... // C22 = .#..........#........###......#. ..................... // C23 = ..#........#.#......#..##....#.# ..................... // C24 = ...#........#.#......#..##....#. ..................... // C25 = ....#........#.#......#..##....# ..................... // C26 = .....#........#.#......#..##.... ..................... // C27 = ......#........#.#......#..##... ..................... // C28 = .......#........#.#......#..##.. ..................... // C29 = ........#........#.#......#..##. ..................... // C30 = .........#........#.#......#..## ..................... // C31 = ..........#........#.#......#..# ..................... // // Number of XORs used is 32 // Maximum XOR input count is 8 // Best possible depth in 4 LUTs = 2 // Best possible depth in 5 LUTs = 2 // Best possible depth in 6 LUTs = 2 // Total XOR inputs 126 // module fec_rot_21 ( input [31:0] c, output [31:0] co ); assign co[0] = c[11] ^ c[20] ^ c[22] ^ c[29]; assign co[1] = c[12] ^ c[21] ^ c[23] ^ c[30]; assign co[2] = c[11] ^ c[13] ^ c[20] ^ c[24] ^ c[29] ^ c[31]; assign co[3] = c[12] ^ c[14] ^ c[21] ^ c[25] ^ c[30]; assign co[4] = c[13] ^ c[15] ^ c[22] ^ c[26] ^ c[31]; assign co[5] = c[14] ^ c[16] ^ c[23] ^ c[27]; assign co[6] = c[15] ^ c[17] ^ c[24] ^ c[28]; assign co[7] = c[16] ^ c[18] ^ c[25] ^ c[29]; assign co[8] = c[17] ^ c[19] ^ c[26] ^ c[30]; assign co[9] = c[18] ^ c[20] ^ c[27] ^ c[31]; assign co[10] = c[19] ^ c[21] ^ c[28]; assign co[11] = c[11]; assign co[12] = c[12]; assign co[13] = c[13]; assign co[14] = c[14]; assign co[15] = c[15]; assign co[16] = c[16]; assign co[17] = c[17]; assign co[18] = c[18]; assign co[19] = c[19]; assign co[20] = c[20]; assign co[21] = c[0] ^ c[11] ^ c[20] ^ c[21] ^ c[22] ^ c[29]; assign co[22] = c[1] ^ c[12] ^ c[21] ^ c[22] ^ c[23] ^ c[30]; assign co[23] = c[2] ^ c[11] ^ c[13] ^ c[20] ^ c[23] ^ c[24] ^ c[29] ^ c[31]; assign co[24] = c[3] ^ c[12] ^ c[14] ^ c[21] ^ c[24] ^ c[25] ^ c[30]; assign co[25] = c[4] ^ c[13] ^ c[15] ^ c[22] ^ c[25] ^ c[26] ^ c[31]; assign co[26] = c[5] ^ c[14] ^ c[16] ^ c[23] ^ c[26] ^ c[27]; assign co[27] = c[6] ^ c[15] ^ c[17] ^ c[24] ^ c[27] ^ c[28]; assign co[28] = c[7] ^ c[16] ^ c[18] ^ c[25] ^ c[28] ^ c[29]; assign co[29] = c[8] ^ c[17] ^ c[19] ^ c[26] ^ c[29] ^ c[30]; assign co[30] = c[9] ^ c[18] ^ c[20] ^ c[27] ^ c[30] ^ c[31]; assign co[31] = c[10] ^ c[19] ^ c[21] ^ c[28] ^ c[31]; endmodule