diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c index 912b59b9c..6f8d11e14 100644 --- a/lib/compress/zstd_lazy.c +++ b/lib/compress/zstd_lazy.c @@ -954,6 +954,30 @@ void ZSTD_row_update(ZSTD_matchState_t* const ms, const BYTE* ip) { ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 0 /* don't use cache */); } +/* Returns the mask width of bits group of which will be set to 1. Given not all + * architectures have easy movemask instruction, this helps to iterate over + * groups of bits easier and faster. + */ +FORCE_INLINE_TEMPLATE U32 +ZSTD_row_matchMaskGroupWidth(const U32 rowEntries) +{ + assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64); + assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES); + (void)rowEntries; +#if defined(ZSTD_ARCH_ARM_NEON) + if (rowEntries == 16) { + return 4; + } + if (rowEntries == 32) { + return 2; + } + if (rowEntries == 64) { + return 1; + } +#endif + return 1; +} + #if defined(ZSTD_ARCH_X86_SSE2) FORCE_INLINE_TEMPLATE ZSTD_VecMask ZSTD_row_getSSEMask(int nbChunks, const BYTE* const src, const BYTE tag, const U32 head) @@ -974,67 +998,78 @@ ZSTD_row_getSSEMask(int nbChunks, const BYTE* const src, const BYTE tag, const U } #endif -/* Returns a ZSTD_VecMask (U32) that has the nth bit set to 1 if the newly-computed "tag" matches - * the hash at the nth position in a row of the tagTable. - * Each row is a circular buffer beginning at the value of "head". So we must rotate the "matches" bitfield - * to match up with the actual layout of the entries within the hashTable */ +#if defined(ZSTD_ARCH_ARM_NEON) FORCE_INLINE_TEMPLATE ZSTD_VecMask -ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 head, const U32 rowEntries) +ZSTD_row_getNEONMask(const U32 rowEntries, const BYTE* const src, const BYTE tag, const U32 headGrouped) +{ + assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64); + if (rowEntries == 16) { + /* vshrn_n_u16 shifts by 4 every u16 and narrows to 8 lower bits. + * After that groups of 4 bits represent the equalMask. We lower + * all bits except the highest in these groups by doing AND with + * 0x88 = 0b10001000. + */ + const uint8x16_t chunk = vld1q_u8(src); + const uint16x8_t equalMask = vreinterpretq_u16_u8(vceqq_u8(chunk, vdupq_n_u8(tag))); + const uint8x8_t res = vshrn_n_u16(equalMask, 4); + const U64 matches = vget_lane_u64(vreinterpret_u64_u8(res), 0); + return ZSTD_rotateRight_U64(matches, headGrouped) & 0x8888888888888888ull; + } else if (rowEntries == 32) { + /* Same idea as with rowEntries == 16 but doing AND with + * 0x55 = 0b01010101. + */ + const uint16x8x2_t chunk = vld2q_u16((const uint16_t*)(const void*)src); + const uint8x16_t chunk0 = vreinterpretq_u8_u16(chunk.val[0]); + const uint8x16_t chunk1 = vreinterpretq_u8_u16(chunk.val[1]); + const uint8x16_t dup = vdupq_n_u8(tag); + const uint8x8_t t0 = vshrn_n_u16(vreinterpretq_u16_u8(vceqq_u8(chunk0, dup)), 6); + const uint8x8_t t1 = vshrn_n_u16(vreinterpretq_u16_u8(vceqq_u8(chunk1, dup)), 6); + const uint8x8_t res = vsli_n_u8(t0, t1, 4); + const U64 matches = vget_lane_u64(vreinterpret_u64_u8(res), 0) ; + return ZSTD_rotateRight_U64(matches, headGrouped) & 0x5555555555555555ull; + } else { /* rowEntries == 64 */ + const uint8x16x4_t chunk = vld4q_u8(src); + const uint8x16_t dup = vdupq_n_u8(tag); + const uint8x16_t cmp0 = vceqq_u8(chunk.val[0], dup); + const uint8x16_t cmp1 = vceqq_u8(chunk.val[1], dup); + const uint8x16_t cmp2 = vceqq_u8(chunk.val[2], dup); + const uint8x16_t cmp3 = vceqq_u8(chunk.val[3], dup); + + const uint8x16_t t0 = vsriq_n_u8(cmp1, cmp0, 1); + const uint8x16_t t1 = vsriq_n_u8(cmp3, cmp2, 1); + const uint8x16_t t2 = vsriq_n_u8(t1, t0, 2); + const uint8x16_t t3 = vsriq_n_u8(t2, t2, 4); + const uint8x8_t t4 = vshrn_n_u16(vreinterpretq_u16_u8(t3), 4); + const U64 matches = vget_lane_u64(vreinterpret_u64_u8(t4), 0); + return ZSTD_rotateRight_U64(matches, headGrouped); + } +} +#endif + +/* Returns a ZSTD_VecMask (U64) that has the nth group (determined by + * ZSTD_row_matchMaskGroupWidth) of bits set to 1 if the newly-computed "tag" + * matches the hash at the nth position in a row of the tagTable. + * Each row is a circular buffer beginning at the value of "headGrouped". So we + * must rotate the "matches" bitfield to match up with the actual layout of the + * entries within the hashTable */ +FORCE_INLINE_TEMPLATE ZSTD_VecMask +ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 headGrouped, const U32 rowEntries) { const BYTE* const src = tagRow + ZSTD_ROW_HASH_TAG_OFFSET; assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64); assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES); + assert(ZSTD_row_matchMaskGroupWidth(rowEntries) * rowEntries <= sizeof(ZSTD_VecMask) * 8); #if defined(ZSTD_ARCH_X86_SSE2) - return ZSTD_row_getSSEMask(rowEntries / 16, src, tag, head); + return ZSTD_row_getSSEMask(rowEntries / 16, src, tag, headGrouped); #else /* SW or NEON-LE */ # if defined(ZSTD_ARCH_ARM_NEON) /* This NEON path only works for little endian - otherwise use SWAR below */ if (MEM_isLittleEndian()) { - if (rowEntries == 16) { - const uint8x16_t chunk = vld1q_u8(src); - const uint16x8_t equalMask = vreinterpretq_u16_u8(vceqq_u8(chunk, vdupq_n_u8(tag))); - const uint16x8_t t0 = vshlq_n_u16(equalMask, 7); - const uint32x4_t t1 = vreinterpretq_u32_u16(vsriq_n_u16(t0, t0, 14)); - const uint64x2_t t2 = vreinterpretq_u64_u32(vshrq_n_u32(t1, 14)); - const uint8x16_t t3 = vreinterpretq_u8_u64(vsraq_n_u64(t2, t2, 28)); - const U16 hi = (U16)vgetq_lane_u8(t3, 8); - const U16 lo = (U16)vgetq_lane_u8(t3, 0); - return ZSTD_rotateRight_U16((hi << 8) | lo, head); - } else if (rowEntries == 32) { - const uint16x8x2_t chunk = vld2q_u16((const U16*)(const void*)src); - const uint8x16_t chunk0 = vreinterpretq_u8_u16(chunk.val[0]); - const uint8x16_t chunk1 = vreinterpretq_u8_u16(chunk.val[1]); - const uint8x16_t equalMask0 = vceqq_u8(chunk0, vdupq_n_u8(tag)); - const uint8x16_t equalMask1 = vceqq_u8(chunk1, vdupq_n_u8(tag)); - const int8x8_t pack0 = vqmovn_s16(vreinterpretq_s16_u8(equalMask0)); - const int8x8_t pack1 = vqmovn_s16(vreinterpretq_s16_u8(equalMask1)); - const uint8x8_t t0 = vreinterpret_u8_s8(pack0); - const uint8x8_t t1 = vreinterpret_u8_s8(pack1); - const uint8x8_t t2 = vsri_n_u8(t1, t0, 2); - const uint8x8x2_t t3 = vuzp_u8(t2, t0); - const uint8x8_t t4 = vsri_n_u8(t3.val[1], t3.val[0], 4); - const U32 matches = vget_lane_u32(vreinterpret_u32_u8(t4), 0); - return ZSTD_rotateRight_U32(matches, head); - } else { /* rowEntries == 64 */ - const uint8x16x4_t chunk = vld4q_u8(src); - const uint8x16_t dup = vdupq_n_u8(tag); - const uint8x16_t cmp0 = vceqq_u8(chunk.val[0], dup); - const uint8x16_t cmp1 = vceqq_u8(chunk.val[1], dup); - const uint8x16_t cmp2 = vceqq_u8(chunk.val[2], dup); - const uint8x16_t cmp3 = vceqq_u8(chunk.val[3], dup); - - const uint8x16_t t0 = vsriq_n_u8(cmp1, cmp0, 1); - const uint8x16_t t1 = vsriq_n_u8(cmp3, cmp2, 1); - const uint8x16_t t2 = vsriq_n_u8(t1, t0, 2); - const uint8x16_t t3 = vsriq_n_u8(t2, t2, 4); - const uint8x8_t t4 = vshrn_n_u16(vreinterpretq_u16_u8(t3), 4); - const U64 matches = vget_lane_u64(vreinterpret_u64_u8(t4), 0); - return ZSTD_rotateRight_U64(matches, head); - } + return ZSTD_row_getNEONMask(rowEntries, src, tag, headGrouped); } # endif /* ZSTD_ARCH_ARM_NEON */ /* SWAR */ @@ -1071,11 +1106,11 @@ ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 head, } matches = ~matches; if (rowEntries == 16) { - return ZSTD_rotateRight_U16((U16)matches, head); + return ZSTD_rotateRight_U16((U16)matches, headGrouped); } else if (rowEntries == 32) { - return ZSTD_rotateRight_U32((U32)matches, head); + return ZSTD_rotateRight_U32((U32)matches, headGrouped); } else { - return ZSTD_rotateRight_U64((U64)matches, head); + return ZSTD_rotateRight_U64((U64)matches, headGrouped); } } #endif @@ -1123,6 +1158,7 @@ size_t ZSTD_RowFindBestMatch( const U32 rowEntries = (1U << rowLog); const U32 rowMask = rowEntries - 1; const U32 cappedSearchLog = MIN(cParams->searchLog, rowLog); /* nb of searches is capped at nb entries per row */ + const U32 groupWidth = ZSTD_row_matchMaskGroupWidth(rowEntries); U32 nbAttempts = 1U << cappedSearchLog; size_t ml=4-1; @@ -1165,15 +1201,15 @@ size_t ZSTD_RowFindBestMatch( U32 const tag = hash & ZSTD_ROW_HASH_TAG_MASK; U32* const row = hashTable + relRow; BYTE* tagRow = (BYTE*)(tagTable + relRow); - U32 const head = *tagRow & rowMask; + U32 const headGrouped = (*tagRow & rowMask) * groupWidth; U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES]; size_t numMatches = 0; size_t currMatch = 0; - ZSTD_VecMask matches = ZSTD_row_getMatchMask(tagRow, (BYTE)tag, head, rowEntries); + ZSTD_VecMask matches = ZSTD_row_getMatchMask(tagRow, (BYTE)tag, headGrouped, rowEntries); /* Cycle through the matches and prefetch */ for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) { - U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask; + U32 const matchPos = ((headGrouped + ZSTD_VecMask_next(matches)) / groupWidth) & rowMask; U32 const matchIndex = row[matchPos]; assert(numMatches < rowEntries); if (matchIndex < lowLimit) @@ -1234,14 +1270,14 @@ size_t ZSTD_RowFindBestMatch( const U32 dmsSize = (U32)(dmsEnd - dmsBase); const U32 dmsIndexDelta = dictLimit - dmsSize; - { U32 const head = *dmsTagRow & rowMask; + { U32 const headGrouped = (*dmsTagRow & rowMask) * groupWidth; U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES]; size_t numMatches = 0; size_t currMatch = 0; - ZSTD_VecMask matches = ZSTD_row_getMatchMask(dmsTagRow, (BYTE)dmsTag, head, rowEntries); + ZSTD_VecMask matches = ZSTD_row_getMatchMask(dmsTagRow, (BYTE)dmsTag, headGrouped, rowEntries); for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) { - U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask; + U32 const matchPos = ((headGrouped + ZSTD_VecMask_next(matches)) / groupWidth) & rowMask; U32 const matchIndex = dmsRow[matchPos]; if (matchIndex < dmsLowestIndex) break;