[Moved] code for 32 bit CRC Polynomial in VHDL

[er.deepak123]

hi friends i hav code for CRC calculation but i am not able to understand the code.. please help me, how they are doing the code and which polynomial is coded in the code.


tc(0) := d(0) xor crc(31); tc(1) := d(1) xor crc(30);
tc(2) := d(2) xor crc(29); tc(3) := d(3) xor crc(28);
ncrc(31) := crc(27);
ncrc(30) := crc(26);
ncrc(29) := tc(0) xor crc(25);
ncrc(28) := tc(1) xor crc(24);
ncrc(27) := tc(2) xor crc(23);
ncrc(26) := tc(0) xor tc(3) xor crc(22);
ncrc(25) := tc(0) xor tc(1) xor crc(21);
ncrc(24) := tc(1) xor tc(2) xor crc(20);
ncrc(23) := tc(2) xor tc(3) xor crc(19);
ncrc(22) := tc(3) xor crc(18);
ncrc(21) := crc(17);
ncrc(20) := crc(16);
ncrc(19) := tc(0) xor crc(15);
ncrc(18) := tc(1) xor crc(14);
ncrc(17) := tc(2) xor crc(13);
ncrc(16) := tc(3) xor crc(12);
ncrc(15) := tc(0) xor crc(11);
ncrc(14) := tc(0) xor tc(1) xor crc(10);
ncrc(13) := tc(0) xor tc(1) xor tc(2) xor crc(9);
ncrc(12) := tc(1) xor tc(2) xor tc(3) xor crc(8);
ncrc(11) := tc(0) xor tc(2) xor tc(3) xor crc(7);
ncrc(10) := tc(0) xor tc(1) xor tc(3) xor crc(6);
ncrc(9) := tc(1) xor tc(2) xor crc(5);
ncrc(8) := tc(0) xor tc(2) xor tc(3) xor crc(4);
ncrc(7) := tc(0) xor tc(1) xor tc(3) xor crc(3);
ncrc(6) := tc(1) xor tc(2) xor crc(2);
ncrc(5) := tc(0) xor tc(2) xor tc(3) xor crc(1);
ncrc(4) := tc(0) xor tc(1) xor tc(3) xor crc(0);
ncrc(3) := tc(0) xor tc(1) xor tc(2);
ncrc(2) := tc(1) xor tc(2) xor tc(3);
ncrc(1) := tc(2) xor tc(3);
ncrc(0) := tc(3);

please help me.
thanx..