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GLideN64/src/CRC32_ARMV8.cpp
2017-07-18 06:26:54 +02:00

69 lines
1.5 KiB
C++

// Copyright (c) 2017-Present Stefan Eschenbacher. All rights reserved.
//
// This ARMv8 CRC32 code, is dual-licensed under GNU General Public License
// version 2 ("GPL") and the Apache License version 2 ("ASL"). For the GPL,
// please see LICENSE. For the ASL, you may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND,
// either express or implied. See the LICENSE file for specific language governing
// rights and limitations of this software.
#include "CRC.h"
#include <arm_acle.h>
void CRC_Init()
{
}
u32 CRC_Calculate( u32 crc, const void * buffer, u32 count )
{
u8 *p;
u32 orig = crc;
p = (u8*) buffer;
// use eight byte crc intrinsic __crc32d if count is high enough.
// __crc32d, __crc32w, __crc32h and __crc32b use polynomial 0x04C11DB7
while (count >= 8) {
crc = __crc32d(crc, *((u64*)p));
p += 8;
count -= 8;
}
if (count >= 4) {
crc = __crc32w(crc, *((u32*)p));
p += 4;
count -= 4;
}
if (count >= 2) {
crc = __crc32h(crc, *((u16*)p));
p += 2;
count -= 2;
}
if (count == 1)
crc = __crc32b(crc, *p);
return crc ^ orig;
}
u32 CRC_Calculate_Strict( u32 crc, const void * buffer, u32 count )
{
return CRC_Calculate(crc, buffer, count);
}
u32 CRC_CalculatePalette(u32 crc, const void * buffer, u32 count )
{
u8 *p;
u32 orig = crc;
p = (u8*) buffer;
while (count--) {
// use two byte intrinsic __crc32h
crc = __crc32h(crc, *((u16*)p));
p += 8;
}
return crc ^ orig;
}