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Pull Match Found Stuff Out of the Loop

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This commit is contained in:
W. Felix Handte
2021-10-05 14:54:37 -04:00
parent 072ffaad67
commit a1ac7205d0
1 changed files with 92 additions and 79 deletions
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lib/compress/zstd_double_fast.c
+35 -22
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@@ -60,7 +60,6 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const U32 hBitsS = cParams->chainLog; const U32 hBitsS = cParams->chainLog;
const BYTE* const base = ms->window.base; const BYTE* const base = ms->window.base;
const BYTE* const istart = (const BYTE*)src; const BYTE* const istart = (const BYTE*)src;
const BYTE* ip = istart;
const BYTE* anchor = istart; const BYTE* anchor = istart;
const U32 endIndex = (U32)((size_t)(istart - base) + srcSize); const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
/* presumes that, if there is a dictionary, it must be using Attach mode */ /* presumes that, if there is a dictionary, it must be using Attach mode */
@@ -70,9 +69,14 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const BYTE* const ilimit = iend - HASH_READ_SIZE; const BYTE* const ilimit = iend - HASH_READ_SIZE;
U32 offset_1=rep[0], offset_2=rep[1]; U32 offset_1=rep[0], offset_2=rep[1];
U32 offsetSaved = 0; U32 offsetSaved = 0;
size_t step = 1;
size_t mLength;
U32 offset;
U32 curr;
const size_t kStepIncr = 1 << kSearchStrength; const size_t kStepIncr = 1 << kSearchStrength;
const BYTE* nextStep = ip + kStepIncr; const BYTE* nextStep;
size_t step;
size_t hl0; size_t hl0;
size_t hs0; size_t hs0;
@@ -89,23 +93,34 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const BYTE* matchl1; const BYTE* matchl1;
// const BYTE* matchs1; // const BYTE* matchs1;
const BYTE* ip = istart;
const BYTE* ip1;
DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_singleSegment_generic"); DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_singleSegment_generic");
/* init */ /* init */
ip += ((ip - prefixLowest) == 0); ip += ((ip - prefixLowest) == 0);
{ {
U32 const curr = (U32)(ip - base); U32 const current = (U32)(ip - base);
U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog); U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
U32 const maxRep = curr - windowLow; U32 const maxRep = current - windowLow;
if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
} }
_start:
step = 1;
nextStep = ip + kStepIncr;
ip1 = ip + step;
if (ip1 >= ilimit) {
goto _cleanup;
}
/* Main Search Loop */ /* Main Search Loop */
while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ do {
size_t mLength; curr = (U32)(ip-base);
U32 offset;
U32 const curr = (U32)(ip-base);
hl0 = ZSTD_hashPtr(ip, hBitsL, 8); hl0 = ZSTD_hashPtr(ip, hBitsL, 8);
hs0 = ZSTD_hashPtr(ip, hBitsS, mls); hs0 = ZSTD_hashPtr(ip, hBitsS, mls);
idxl0 = hashLong[hl0]; idxl0 = hashLong[hl0];
@@ -151,10 +166,17 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
#if defined(__aarch64__) #if defined(__aarch64__)
PREFETCH_L1(ip+256); PREFETCH_L1(ip+256);
#endif #endif
continue; } while (ip < ilimit);
_cleanup:
/* save reps for next block */
rep[0] = offset_1 ? offset_1 : offsetSaved;
rep[1] = offset_2 ? offset_2 : offsetSaved;
/* Return the last literals size */
return (size_t)(iend - anchor);
_search_next_long: _search_next_long:
{ hl1 = ZSTD_hashPtr(ip+1, hBitsL, 8); { hl1 = ZSTD_hashPtr(ip+1, hBitsL, 8);
idxl1 = hashLong[hl1]; idxl1 = hashLong[hl1];
matchl1 = base + idxl1; matchl1 = base + idxl1;
@@ -217,16 +239,7 @@ _match_stored:
continue; /* faster when present ... (?) */ continue; /* faster when present ... (?) */
} } } }
step = 1; goto _start;
nextStep = ip + kStepIncr;
} /* while (ip < ilimit) */
/* save reps for next block */
rep[0] = offset_1 ? offset_1 : offsetSaved;
rep[1] = offset_2 ? offset_2 : offsetSaved;
/* Return the last literals size */
return (size_t)(iend - anchor);
} }