diff options
Diffstat (limited to 'third_party/zlib/fill_window_sse.c')
| -rw-r--r-- | third_party/zlib/fill_window_sse.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/third_party/zlib/fill_window_sse.c b/third_party/zlib/fill_window_sse.c new file mode 100644 index 00000000..a841c999 --- /dev/null +++ b/third_party/zlib/fill_window_sse.c @@ -0,0 +1,182 @@ +/* + * Fill Window with SSE2-optimized hash shifting + * + * Copyright (C) 2013 Intel Corporation + * Authors: + * Arjan van de Ven <arjan@linux.intel.com> + * Jim Kukunas <james.t.kukunas@linux.intel.com> + * + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +#include "deflate.h" + +#ifdef DEFLATE_FILL_WINDOW_SSE2 + +#define UPDATE_HASH(s,h,i) \ + {\ + if (s->level < 6) { \ + h = (3483 * (s->window[i]) +\ + 23081* (s->window[i+1]) +\ + 6954 * (s->window[i+2]) +\ + 20947* (s->window[i+3])) & s->hash_mask;\ + } else {\ + h = (25881* (s->window[i]) +\ + 24674* (s->window[i+1]) +\ + 25811* (s->window[i+2])) & s->hash_mask;\ + }\ + }\ + +extern int deflate_read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); + +#include <immintrin.h> + +void fill_window_sse(deflate_state *s) +{ + const __m128i xmm_wsize = _mm_set1_epi16(s->w_size); + + register unsigned n; + register Posf *p; + unsigned more; /* Amount of free space at the end of the window. */ + uInt wsize = s->w_size; + + Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead"); + + do { + more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); + + /* Deal with !@#$% 64K limit: */ + if (sizeof(int) <= 2) { + if (more == 0 && s->strstart == 0 && s->lookahead == 0) { + more = wsize; + + } else if (more == (unsigned)(-1)) { + /* Very unlikely, but possible on 16 bit machine if + * strstart == 0 && lookahead == 1 (input done a byte at time) + */ + more--; + } + } + + /* If the window is almost full and there is insufficient lookahead, + * move the upper half to the lower one to make room in the upper half. + */ + if (s->strstart >= wsize+MAX_DIST(s)) { + + zmemcpy(s->window, s->window+wsize, (unsigned)wsize); + s->match_start -= wsize; + s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ + s->block_start -= (long) wsize; + + /* Slide the hash table (could be avoided with 32 bit values + at the expense of memory usage). We slide even when level == 0 + to keep the hash table consistent if we switch back to level > 0 + later. (Using level 0 permanently is not an optimal usage of + zlib, so we don't care about this pathological case.) + */ + n = s->hash_size; + p = &s->head[n]; + p -= 8; + do { + __m128i value, result; + + value = _mm_loadu_si128((__m128i *)p); + result = _mm_subs_epu16(value, xmm_wsize); + _mm_storeu_si128((__m128i *)p, result); + + p -= 8; + n -= 8; + } while (n > 0); + + n = wsize; +#ifndef FASTEST + p = &s->prev[n]; + p -= 8; + do { + __m128i value, result; + + value = _mm_loadu_si128((__m128i *)p); + result = _mm_subs_epu16(value, xmm_wsize); + _mm_storeu_si128((__m128i *)p, result); + + p -= 8; + n -= 8; + } while (n > 0); +#endif + more += wsize; + } + if (s->strm->avail_in == 0) break; + + /* If there was no sliding: + * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && + * more == window_size - lookahead - strstart + * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) + * => more >= window_size - 2*WSIZE + 2 + * In the BIG_MEM or MMAP case (not yet supported), + * window_size == input_size + MIN_LOOKAHEAD && + * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. + * Otherwise, window_size == 2*WSIZE so more >= 2. + * If there was sliding, more >= WSIZE. So in all cases, more >= 2. + */ + Assert(more >= 2, "more < 2"); + + n = deflate_read_buf(s->strm, + s->window + s->strstart + s->lookahead, + more); + s->lookahead += n; + + /* Initialize the hash value now that we have some input: */ + if (s->lookahead >= MIN_MATCH) { + uInt str = s->strstart; + s->ins_h = s->window[str]; + if (str >= 1) + UPDATE_HASH(s, s->ins_h, str + 1 - (MIN_MATCH-1)); +#if MIN_MATCH != 3 + Call UPDATE_HASH() MIN_MATCH-3 more times +#endif + } + /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, + * but this is not important since only literal bytes will be emitted. + */ + + } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); + + /* If the WIN_INIT bytes after the end of the current data have never been + * written, then zero those bytes in order to avoid memory check reports of + * the use of uninitialized (or uninitialised as Julian writes) bytes by + * the longest match routines. Update the high water mark for the next + * time through here. WIN_INIT is set to MAX_MATCH since the longest match + * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. + */ + if (s->high_water < s->window_size) { + ulg curr = s->strstart + (ulg)(s->lookahead); + ulg init; + + if (s->high_water < curr) { + /* Previous high water mark below current data -- zero WIN_INIT + * bytes or up to end of window, whichever is less. + */ + init = s->window_size - curr; + if (init > WIN_INIT) + init = WIN_INIT; + zmemzero(s->window + curr, (unsigned)init); + s->high_water = curr + init; + } + else if (s->high_water < (ulg)curr + WIN_INIT) { + /* High water mark at or above current data, but below current data + * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up + * to end of window, whichever is less. + */ + init = (ulg)curr + WIN_INIT - s->high_water; + if (init > s->window_size - s->high_water) + init = s->window_size - s->high_water; + zmemzero(s->window + s->high_water, (unsigned)init); + s->high_water += init; + } + } + + Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, + "not enough room for search"); +} + +#endif /* DEFLATE_FILL_WINDOW_SSE2 */ |