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/*-
* Copyright (c) 2014-2018 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#ifdef HAVE_X86INTRIN_H
#if !defined(_MSC_VER) && !defined(_lint)
#include <x86intrin.h>
#endif
#endif
/* 16B alignment */
#define WT_ALIGNED_16(p) (((uintptr_t)(p) & 0x0f) == 0)
#define WT_VECTOR_SIZE 16 /* chunk size */
#if defined(HAVE_ARM_NEON_INTRIN_H)
#include <arm_neon.h>
/*
* _mm_movemask_epi8_neon --
* Creates a 16-bit mask from the most significant bits of the 16 signed
* or unsigned 8-bit integers.
*/
static inline uint16_t
_mm_movemask_epi8_neon(const uint8x16_t data)
{
uint64x1_t p;
p = vset_lane_u64(0x8040201008040201, p, 0);
uint8x16_t powers = vcombine_u8(p, p);
uint8x16_t zero8x16 = vdupq_n_s8(0);
int8x16_t input = vcltq_s8((int8x16_t)data, (int8x16_t)zero8x16);
uint64x2_t mask = vpaddlq_u32(
vpaddlq_u16(vpaddlq_u8(vandq_u8((uint8x16_t)input, powers))));
uint16_t output;
output =
((vgetq_lane_u8(mask, 8) << 8) | (vgetq_lane_u8(mask, 0) << 0));
return (output);
}
#endif
/*
* __wt_lex_compare --
* Lexicographic comparison routine.
*
* Returns:
* < 0 if user_item is lexicographically < tree_item
* = 0 if user_item is lexicographically = tree_item
* > 0 if user_item is lexicographically > tree_item
*
* We use the names "user" and "tree" so it's clear in the btree code which
* the application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare(const WT_ITEM *user_item, const WT_ITEM *tree_item)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz);
userp = user_item->data;
treep = tree_item->data;
#ifdef HAVE_X86INTRIN_H
/* Use vector instructions if we'll execute at least 2 of them. */
if (len >= WT_VECTOR_SIZE * 2) {
size_t remain;
__m128i res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = _mm_load_si128((const __m128i *)userp);
t = _mm_load_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
else
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = _mm_loadu_si128((const __m128i *)userp);
t = _mm_loadu_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
len += remain;
}
#elif defined(HAVE_ARM_NEON_INTRIN_H)
/* Use vector instructions if we'll execute at least 1 of them. */
if (len >= WT_VECTOR_SIZE) {
size_t remain;
uint8x16_t res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = vld1q_u8(userp);
t = vld1q_u8(treep);
res_eq = vceqq_u8(u, t);
if (_mm_movemask_epi8_neon(res_eq) != 65535)
break;
}
len += remain;
}
#endif
/*
* Use the non-vectorized version for the remaining bytes and for the
* small key sizes.
*/
for (; len > 0; --len, ++userp, ++treep)
if (*userp != *treep)
return (*userp < *treep ? -1 : 1);
/* Contents are equal up to the smallest length. */
return ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
}
/*
* __wt_compare --
* The same as __wt_lex_compare, but using the application's collator
* function when configured.
*/
static inline int
__wt_compare(WT_SESSION_IMPL *session, WT_COLLATOR *collator,
const WT_ITEM *user_item, const WT_ITEM *tree_item, int *cmpp)
{
if (collator == NULL) {
*cmpp = __wt_lex_compare(user_item, tree_item);
return (0);
}
return (collator->compare(
collator, &session->iface, user_item, tree_item, cmpp));
}
/*
* __wt_lex_compare_skip --
* Lexicographic comparison routine, skipping leading bytes.
*
* Returns:
* < 0 if user_item is lexicographically < tree_item
* = 0 if user_item is lexicographically = tree_item
* > 0 if user_item is lexicographically > tree_item
*
* We use the names "user" and "tree" so it's clear in the btree code which
* the application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare_skip(
const WT_ITEM *user_item, const WT_ITEM *tree_item, size_t *matchp)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz) - *matchp;
userp = (const uint8_t *)user_item->data + *matchp;
treep = (const uint8_t *)tree_item->data + *matchp;
#ifdef HAVE_X86INTRIN_H
/* Use vector instructions if we'll execute at least 2 of them. */
if (len >= WT_VECTOR_SIZE * 2) {
size_t remain;
__m128i res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = _mm_load_si128((const __m128i *)userp);
t = _mm_load_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
else
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = _mm_loadu_si128((const __m128i *)userp);
t = _mm_loadu_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
len += remain;
}
#elif defined(HAVE_ARM_NEON_INTRIN_H)
/* Use vector instructions if we'll execute at least 1 of them. */
if (len >= WT_VECTOR_SIZE) {
size_t remain;
uint8x16_t res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0;
len -= WT_VECTOR_SIZE,
userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = vld1q_u8(userp);
t = vld1q_u8(treep);
res_eq = vceqq_u8(u, t);
if (_mm_movemask_epi8_neon(res_eq) != 65535)
break;
}
len += remain;
}
#endif
/*
* Use the non-vectorized version for the remaining bytes and for the
* small key sizes.
*/
for (; len > 0; --len, ++userp, ++treep, ++*matchp)
if (*userp != *treep)
return (*userp < *treep ? -1 : 1);
/* Contents are equal up to the smallest length. */
return ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
}
/*
* __wt_compare_skip --
* The same as __wt_lex_compare_skip, but using the application's collator
* function when configured.
*/
static inline int
__wt_compare_skip(WT_SESSION_IMPL *session, WT_COLLATOR *collator,
const WT_ITEM *user_item, const WT_ITEM *tree_item, int *cmpp,
size_t *matchp)
{
if (collator == NULL) {
*cmpp = __wt_lex_compare_skip(user_item, tree_item, matchp);
return (0);
}
return (collator->compare(
collator, &session->iface, user_item, tree_item, cmpp));
}
/*
* __wt_lex_compare_short --
* Lexicographic comparison routine for short keys.
*
* Returns:
* < 0 if user_item is lexicographically < tree_item
* = 0 if user_item is lexicographically = tree_item
* > 0 if user_item is lexicographically > tree_item
*
* We use the names "user" and "tree" so it's clear in the btree code which
* the application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare_short(const WT_ITEM *user_item, const WT_ITEM *tree_item)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz);
userp = user_item->data;
treep = tree_item->data;
/*
* The maximum packed uint64_t is 9B, catch row-store objects using
* packed record numbers as keys.
*
* Don't use a #define to compress this case statement: gcc7 complains
* about implicit fallthrough and doesn't support explicit fallthrough
* comments in macros.
*/
#define WT_COMPARE_SHORT_MAXLEN 9
switch (len) {
case 9:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 8:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 7:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 6:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 5:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 4:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 3:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 2:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 1:
if (*userp != *treep)
break;
/* Contents are equal up to the smallest length. */
return ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
}
return (*userp < *treep ? -1 : 1);
}
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