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-------------------------------------------------------------------------------- -- Copyright (C) 1999-2008 Easics NV. -- This source file may be used and distributed without restriction -- provided that this copyright statement is not removed from the file -- and that any derivative work contains the original copyright notice -- and the associated disclaimer. -- -- THIS SOURCE FILE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS -- OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED -- WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. -- -- Purpose : synthesizable CRC function -- * polynomial: (0 1 2 4 5 7 8 10 11 12 16 22 23 26 32) -- * data width: 4 -- -- Info : tools@easics.be -- http://www.easics.com -------------------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; package PCK_CRC32_D4 is -- polynomial: (0 1 2 4 5 7 8 10 11 12 16 22 23 26 32) -- data width: 4 -- convention: the first serial bit is D[3] function nextCRC32_D4 (Data: std_logic_vector(3 downto 0); crc: std_logic_vector(31 downto 0)) return std_logic_vector; end PCK_CRC32_D4; package body PCK_CRC32_D4 is -- polynomial: (0 1 2 4 5 7 8 10 11 12 16 22 23 26 32) -- data width: 4 -- convention: the first serial bit is D[3] function nextCRC32_D4 (Data: std_logic_vector(3 downto 0); crc: std_logic_vector(31 downto 0)) return std_logic_vector is variable d: std_logic_vector(3 downto 0); variable c: std_logic_vector(31 downto 0); variable newcrc: std_logic_vector(31 downto 0); begin d := Data; c := crc; newcrc(0) := d(0) xor c(28); newcrc(1) := d(1) xor d(0) xor c(28) xor c(29); newcrc(2) := d(2) xor d(1) xor d(0) xor c(28) xor c(29) xor c(30); newcrc(3) := d(3) xor d(2) xor d(1) xor c(29) xor c(30) xor c(31); newcrc(4) := d(3) xor d(2) xor d(0) xor c(0) xor c(28) xor c(30) xor c(31); newcrc(5) := d(3) xor d(1) xor d(0) xor c(1) xor c(28) xor c(29) xor c(31); newcrc(6) := d(2) xor d(1) xor c(2) xor c(29) xor c(30); newcrc(7) := d(3) xor d(2) xor d(0) xor c(3) xor c(28) xor c(30) xor c(31); newcrc(8) := d(3) xor d(1) xor d(0) xor c(4) xor c(28) xor c(29) xor c(31); newcrc(9) := d(2) xor d(1) xor c(5) xor c(29) xor c(30); newcrc(10) := d(3) xor d(2) xor d(0) xor c(6) xor c(28) xor c(30) xor c(31); newcrc(11) := d(3) xor d(1) xor d(0) xor c(7) xor c(28) xor c(29) xor c(31); newcrc(12) := d(2) xor d(1) xor d(0) xor c(8) xor c(28) xor c(29) xor c(30); newcrc(13) := d(3) xor d(2) xor d(1) xor c(9) xor c(29) xor c(30) xor c(31); newcrc(14) := d(3) xor d(2) xor c(10) xor c(30) xor c(31); newcrc(15) := d(3) xor c(11) xor c(31); newcrc(16) := d(0) xor c(12) xor c(28); newcrc(17) := d(1) xor c(13) xor c(29); newcrc(18) := d(2) xor c(14) xor c(30); newcrc(19) := d(3) xor c(15) xor c(31); newcrc(20) := c(16); newcrc(21) := c(17); newcrc(22) := d(0) xor c(18) xor c(28); newcrc(23) := d(1) xor d(0) xor c(19) xor c(28) xor c(29); newcrc(24) := d(2) xor d(1) xor c(20) xor c(29) xor c(30); newcrc(25) := d(3) xor d(2) xor c(21) xor c(30) xor c(31); newcrc(26) := d(3) xor d(0) xor c(22) xor c(28) xor c(31); newcrc(27) := d(1) xor c(23) xor c(29); newcrc(28) := d(2) xor c(24) xor c(30); newcrc(29) := d(3) xor c(25) xor c(31); newcrc(30) := c(26); newcrc(31) := c(27); return newcrc; end nextCRC32_D4; end PCK_CRC32_D4;