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/* Copyright (C) 2017 International Business Machines Corp.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define CRC_TABLE
#define FAST_ZERO_TABLE
#include "acconfig.h"
#include "include/int_types.h"
#include "crc32c_ppc_constants.h"
#include "reverse.h"
#include <stdlib.h>
#include <strings.h>
#define VMX_ALIGN 16
#define VMX_ALIGN_MASK (VMX_ALIGN-1)
#ifdef HAVE_PPC64LE
#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;
}
#else
static unsigned int crc32_align(unsigned int crc, unsigned char const *p,
unsigned long len)
{
while (len--)
crc = crc_table[((crc >> 24) ^ *p++) & 0xff] ^ (crc << 8);
return crc;
}
#endif
static inline unsigned long polynomial_multiply(unsigned int a, unsigned int b) {
vector unsigned int va = {a, 0, 0, 0};
vector unsigned int vb = {b, 0, 0, 0};
vector unsigned long vt;
__asm__("vpmsumw %0,%1,%2" : "=v"(vt) : "v"(va), "v"(vb));
return vt[0];
}
unsigned int barrett_reduction(unsigned long val);
static inline unsigned int gf_multiply(unsigned int a, unsigned int b) {
return barrett_reduction(polynomial_multiply(a, b));
}
unsigned int append_zeros(unsigned int crc, unsigned long length) {
unsigned long i = 0;
while (length) {
if (length & 1) {
crc = gf_multiply(crc, crc_zero[i]);
}
i++;
length /= 2;
}
return crc;
}
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.
*/
uint32_t ceph_crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len)
{
if (!data) {
/* Handle the NULL buffer case. */
#ifdef REFLECT
crc = reverse_bits(crc);
#endif
crc = append_zeros(crc, len);
#ifdef REFLECT
crc = reverse_bits(crc);
#endif
} else {
/* Handle the valid buffer case. */
crc = crc32_vpmsum(crc, data, (unsigned long)len);
}
return crc;
}
#else /* HAVE_PPC64LE */
/* 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 ceph_crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len)
{
return 0;
}
#endif /* HAVE_PPC64LE */
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