diff options
Diffstat (limited to 'src/rocksdb/util/crc32c_ppc.c')
-rw-r--r-- | src/rocksdb/util/crc32c_ppc.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/src/rocksdb/util/crc32c_ppc.c b/src/rocksdb/util/crc32c_ppc.c new file mode 100644 index 00000000..3c517c88 --- /dev/null +++ b/src/rocksdb/util/crc32c_ppc.c @@ -0,0 +1,95 @@ +// Copyright (c) 2017 International Business Machines Corp. +// All rights reserved. +// This source code is licensed under the BSD-style license found in the +// LICENSE file in the root directory of this source tree. An additional grant +// of patent rights can be found in the PATENTS file in the same directory. +// This source code is also licensed under the GPLv2 license found in the +// COPYING file in the root directory of this source tree. + +#define CRC_TABLE +#include <inttypes.h> +#include <stdlib.h> +#include <strings.h> +#include "util/crc32c_ppc_constants.h" + +#define VMX_ALIGN 16 +#define VMX_ALIGN_MASK (VMX_ALIGN - 1) + +#ifdef REFLECT +static unsigned int crc32_align(unsigned int crc, unsigned char const *p, + unsigned long len) { + while (len--) crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8); + return crc; +} +#endif + +#ifdef HAVE_POWER8 +unsigned int __crc32_vpmsum(unsigned int crc, unsigned char const *p, + unsigned long len); + +static uint32_t crc32_vpmsum(uint32_t crc, unsigned char const *data, + unsigned len) { + unsigned int prealign; + unsigned int tail; + +#ifdef CRC_XOR + crc ^= 0xffffffff; +#endif + + if (len < VMX_ALIGN + VMX_ALIGN_MASK) { + crc = crc32_align(crc, data, (unsigned long)len); + goto out; + } + + if ((unsigned long)data & VMX_ALIGN_MASK) { + prealign = VMX_ALIGN - ((unsigned long)data & VMX_ALIGN_MASK); + crc = crc32_align(crc, data, prealign); + len -= prealign; + data += prealign; + } + + crc = __crc32_vpmsum(crc, data, (unsigned long)len & ~VMX_ALIGN_MASK); + + tail = len & VMX_ALIGN_MASK; + if (tail) { + data += len & ~VMX_ALIGN_MASK; + crc = crc32_align(crc, data, tail); + } + +out: +#ifdef CRC_XOR + crc ^= 0xffffffff; +#endif + + return crc; +} + +/* This wrapper function works around the fact that crc32_vpmsum + * does not gracefully handle the case where the data pointer is NULL. There + * may be room for performance improvement here. + */ +uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len) { + unsigned char *buf2; + + if (!data) { + buf2 = (unsigned char *)malloc(len); + bzero(buf2, len); + crc = crc32_vpmsum(crc, buf2, len); + free(buf2); + } else { + crc = crc32_vpmsum(crc, data, (unsigned long)len); + } + return crc; +} + +#else /* HAVE_POWER8 */ + +/* This symbol has to exist on non-ppc architectures (and on legacy + * ppc systems using power7 or below) in order to compile properly + * there, even though it won't be called. + */ +uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len) { + return 0; +} + +#endif /* HAVE_POWER8 */ |