1/* 7zCrcOpt.c -- CRC32 calculation : optimized version
22009-11-23 : Igor Pavlov : Public domain */
3
4#include "CpuArch.h"
5
6#ifdef MY_CPU_LE
7
8#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
9
10UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
11{
12  const Byte *p = (const Byte *)data;
13  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
14    v = CRC_UPDATE_BYTE_2(v, *p);
15  for (; size >= 4; size -= 4, p += 4)
16  {
17    v ^= *(const UInt32 *)p;
18    v =
19      table[0x300 + (v & 0xFF)] ^
20      table[0x200 + ((v >> 8) & 0xFF)] ^
21      table[0x100 + ((v >> 16) & 0xFF)] ^
22      table[0x000 + ((v >> 24))];
23  }
24  for (; size > 0; size--, p++)
25    v = CRC_UPDATE_BYTE_2(v, *p);
26  return v;
27}
28
29UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
30{
31  return CrcUpdateT4(v, data, size, table);
32}
33
34#endif
35