rocksdb/util/crc32c_arm64.cc
Yuqi Gu 03c7ae24c2 RocksDB CRC32c optimization with ARMv8 Intrinsic (#5221)
Summary:
1. Add Arm linear crc32c implemtation for RocksDB.
2. Arm runtime check for crc32
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5221

Differential Revision: D15013685

Pulled By: siying

fbshipit-source-id: 2c2983743d26656d93f212dc7c1a3cf66a1acf12
2019-04-30 10:59:05 -07:00

57 lines
1.4 KiB
C++

// Copyright (c) 2018, Arm Limited and affiliates. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "util/crc32c_arm64.h"
#if defined(__linux__) && defined(HAVE_ARM64_CRC)
#include <asm/hwcap.h>
#include <sys/auxv.h>
#ifndef HWCAP_CRC32
#define HWCAP_CRC32 (1 << 7)
#endif
uint32_t crc32c_runtime_check(void) {
uint64_t auxv = getauxval(AT_HWCAP);
return (auxv & HWCAP_CRC32) != 0;
}
uint32_t crc32c_arm64(uint32_t crc, unsigned char const *data,
unsigned len) {
const uint8_t *buf1;
const uint16_t *buf2;
const uint32_t *buf4;
const uint64_t *buf8;
int64_t length = (int64_t)len;
crc ^= 0xffffffff;
buf8 = (const uint64_t *)data;
while ((length -= sizeof(uint64_t)) >= 0) {
crc = __crc32cd(crc, *buf8++);
}
/* The following is more efficient than the straight loop */
buf4 = (const uint32_t *)buf8;
if (length & sizeof(uint32_t)) {
crc = __crc32cw(crc, *buf4++);
length -= 4;
}
buf2 = (const uint16_t *)buf4;
if (length & sizeof(uint16_t)) {
crc = __crc32ch(crc, *buf2++);
length -= 2;
}
buf1 = (const uint8_t *)buf2;
if (length & sizeof(uint8_t))
crc = __crc32cb(crc, *buf1);
crc ^= 0xffffffff;
return crc;
}
#endif