/* 7zCrcOpt.c -- CRC32 calculation : optimized version | |
2009-11-23 : Igor Pavlov : Public domain */ | |
#include "CpuArch.h" | |
#ifdef MY_CPU_LE | |
#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8)) | |
UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table) | |
{ | |
const Byte *p = (const Byte *)data; | |
for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++) | |
v = CRC_UPDATE_BYTE_2(v, *p); | |
for (; size >= 4; size -= 4, p += 4) | |
{ | |
v ^= *(const UInt32 *)p; | |
v = | |
table[0x300 + (v & 0xFF)] ^ | |
table[0x200 + ((v >> 8) & 0xFF)] ^ | |
table[0x100 + ((v >> 16) & 0xFF)] ^ | |
table[0x000 + ((v >> 24))]; | |
} | |
for (; size > 0; size--, p++) | |
v = CRC_UPDATE_BYTE_2(v, *p); | |
return v; | |
} | |
UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table) | |
{ | |
return CrcUpdateT4(v, data, size, table); | |
} | |
#endif |