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flate, zstd: Shave some bytes off amd64 matchLen #963

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Merged
merged 2 commits into from
May 30, 2024
Merged

flate, zstd: Shave some bytes off amd64 matchLen #963

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d83e809
flate, zstd: Shave some bytes off amd64 matchLen
greatroar May 27, 2024
61363c6
Merge branch 'master' into matchlen
klauspost May 30, 2024
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10 changes: 4 additions & 6 deletions flate/matchlen_amd64.s
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@
#include "textflag.h"

// func matchLen(a []byte, b []byte) int
// Requires: BMI
TEXT ·matchLen(SB), NOSPLIT, $0-56
MOVQ a_base+0(FP), AX
MOVQ b_base+24(FP), CX
Expand All @@ -17,17 +16,16 @@ TEXT ·matchLen(SB), NOSPLIT, $0-56
JB matchlen_match4_standalone

matchlen_loopback_standalone:
MOVQ (AX)(SI*1), BX
XORQ (CX)(SI*1), BX
TESTQ BX, BX
JZ matchlen_loop_standalone
MOVQ (AX)(SI*1), BX
XORQ (CX)(SI*1), BX
JZ matchlen_loop_standalone

#ifdef GOAMD64_v3
TZCNTQ BX, BX
#else
BSFQ BX, BX
#endif
SARQ $0x03, BX
SHRL $0x03, BX
LEAL (SI)(BX*1), SI
JMP gen_match_len_end

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10 changes: 4 additions & 6 deletions zstd/matchlen_amd64.s
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@
#include "textflag.h"

// func matchLen(a []byte, b []byte) int
// Requires: BMI
TEXT ·matchLen(SB), NOSPLIT, $0-56
MOVQ a_base+0(FP), AX
MOVQ b_base+24(FP), CX
Expand All @@ -17,17 +16,16 @@ TEXT ·matchLen(SB), NOSPLIT, $0-56
JB matchlen_match4_standalone

matchlen_loopback_standalone:
MOVQ (AX)(SI*1), BX
XORQ (CX)(SI*1), BX
TESTQ BX, BX
JZ matchlen_loop_standalone
MOVQ (AX)(SI*1), BX
XORQ (CX)(SI*1), BX
JZ matchlen_loop_standalone

#ifdef GOAMD64_v3
TZCNTQ BX, BX
#else
BSFQ BX, BX
#endif
SARQ $0x03, BX
SHRL $0x03, BX
LEAL (SI)(BX*1), SI
JMP gen_match_len_end

Expand Down