From 7ca1e2aa56f23b1766e8f5f65c431d18abd58985 Mon Sep 17 00:00:00 2001 From: Archana R Date: Mon, 10 Jan 2022 02:15:25 -0600 Subject: [PATCH] internal/bytealg: optimize index function for ppc64le/power9 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Optimized index2to16 loop by unrolling the loop by 4. Multiple benchmark tests show performance improvement on POWER9. Similar improvements are seen on POWER10. Added tests to ensure changes work fine. name old time/op new time/op delta Index/10 18.3ns ± 0% 19.7ns ±25% ~ Index/32 75.3ns ± 0% 69.2ns ± 0% -8.22% Index/4K 5.53µs ± 0% 3.69µs ± 0% -33.20% Index/4M 5.64ms ± 0% 3.75ms ± 0% -33.55% Index/64M 92.9ms ± 0% 61.6ms ± 0% -33.69% IndexHard2 1.41ms ± 0% 0.93ms ± 0% -33.75% CountHard2 1.41ms ± 0% 0.93ms ± 0% -33.75% Change-Id: If9331df6a141a4716724b8cb648d2b91bdf17e5f Reviewed-on: https://go-review.googlesource.com/c/go/+/377016 Reviewed-by: Cherry Mui Reviewed-by: David Chase Reviewed-by: Paul Murphy TryBot-Result: Gopher Robot Run-TryBot: Archana Ravindar --- src/bytes/bytes_test.go | 30 +++++ src/internal/bytealg/index_ppc64x.s | 198 +++++++++++++++++----------- 2 files changed, 149 insertions(+), 79 deletions(-) diff --git a/src/bytes/bytes_test.go b/src/bytes/bytes_test.go index b702efb239..985aa0b147 100644 --- a/src/bytes/bytes_test.go +++ b/src/bytes/bytes_test.go @@ -140,6 +140,36 @@ var indexTests = []BinOpTest{ {"abc", "c", 2}, {"abc", "x", -1}, {"barfoobarfooyyyzzzyyyzzzyyyzzzyyyxxxzzzyyy", "x", 33}, + {"fofofofooofoboo", "oo", 7}, + {"fofofofofofoboo", "ob", 11}, + {"fofofofofofoboo", "boo", 12}, + {"fofofofofofoboo", "oboo", 11}, + {"fofofofofoooboo", "fooo", 8}, + {"fofofofofofoboo", "foboo", 10}, + {"fofofofofofoboo", "fofob", 8}, + {"fofofofofofofoffofoobarfoo", "foffof", 12}, + {"fofofofofoofofoffofoobarfoo", "foffof", 13}, + {"fofofofofofofoffofoobarfoo", "foffofo", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofo", 13}, + {"fofofofofoofofoffofoobarfoo", "foffofoo", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoo", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofoob", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoob", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofooba", 13}, + {"fofofofofofofoffofoobarfoo", "foffofooba", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofoobar", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoobar", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofoobarf", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoobarf", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofoobarfo", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoobarfo", 12}, + {"fofofofofoofofoffofoobarfoo", "foffofoobarfoo", 13}, + {"fofofofofofofoffofoobarfoo", "foffofoobarfoo", 12}, + {"fofofofofoofofoffofoobarfoo", "ofoffofoobarfoo", 12}, + {"fofofofofofofoffofoobarfoo", "ofoffofoobarfoo", 11}, + {"fofofofofoofofoffofoobarfoo", "fofoffofoobarfoo", 11}, + {"fofofofofofofoffofoobarfoo", "fofoffofoobarfoo", 10}, + {"fofofofofoofofoffofoobarfoo", "foobars", -1}, {"foofyfoobarfoobar", "y", 4}, {"oooooooooooooooooooooo", "r", -1}, {"oxoxoxoxoxoxoxoxoxoxoxoy", "oy", 22}, diff --git a/src/internal/bytealg/index_ppc64x.s b/src/internal/bytealg/index_ppc64x.s index 18e57fb033..38442ce27c 100644 --- a/src/internal/bytealg/index_ppc64x.s +++ b/src/internal/bytealg/index_ppc64x.s @@ -17,8 +17,9 @@ // NOTE: There is a power9 implementation that // improves performance by 10-15% on little -// endian for some of the benchmarks, but -// work is still needed for a big endian +// endian for some of the benchmarks. +// Unrolled index2to16 loop by 4 on ppc64le/power9 +// Work is still needed for a big endian // implementation on power9. //go:build ppc64 || ppc64le @@ -46,8 +47,8 @@ DATA byteswap<>+8(SB)/8, $0x0f0e0d0c0b0a0908 GLOBL byteswap<>+0(SB), RODATA, $16 TEXT ·Index(SB),NOSPLIT|NOFRAME,$0-56 - // R3 = byte array pointer - // R4 = length + // R3 = byte array pointer + // R4 = length MOVD R6, R5 // R5 = separator pointer MOVD R7, R6 // R6 = separator length @@ -97,16 +98,6 @@ power8: #define LASTSTR R27 #define ONES V20 #define SWAP V21 -#define V0_ VS32 -#define V1_ VS33 -#define V2_ VS34 -#define V3_ VS35 -#define V4_ VS36 -#define V5_ VS37 -#define V6_ VS38 -#define V7_ VS39 -#define V8_ VS40 -#define V9_ VS41 #define SWAP_ VS53 TEXT indexbody<>(SB), NOSPLIT|NOFRAME, $0 CMP R6, R4 // Compare lengths @@ -129,7 +120,7 @@ TEXT indexbody<>(SB), NOSPLIT|NOFRAME, $0 BGE CR4, loadge16 // Load for len(sep) >= 16 SUB R6, R16, R9 // 16-len of sep SLD $3, R9 // Set up for VSLO - MTVSRD R9, V9_ // Set up for VSLO + MTVSRD R9, V9 // Set up for VSLO VSLDOI $8, V9, V9, V9 // Set up for VSLO VSLO ONES, V9, SEPMASK // Mask for separator len(sep) < 16 @@ -140,9 +131,9 @@ loadge16: BGT sepcross16 // Sep crosses 16 byte boundary RLDICR $0, R5, $59, R8 // Adjust addr to 16 byte container - VLOADSWAP(R8, R0, V0, V0_)// Load 16 bytes @R8 into V0 + VLOADSWAP(R8, R0, V0, V0) // Load 16 bytes @R8 into V0 SLD $3, R9 // Set up shift count for VSLO - MTVSRD R9, V8_ // Set up shift count for VSLO + MTVSRD R9, V8 // Set up shift count for VSLO VSLDOI $8, V8, V8, V8 VSLO V0, V8, V0 // Shift by start byte @@ -150,7 +141,7 @@ loadge16: BR index2plus sepcross16: - VLOADSWAP(R5, R0, V0, V0_) // Load 16 bytes @R5 into V0 + VLOADSWAP(R5, R0, V0, V0) // Load 16 bytes @R5 into V0 VAND V0, SEPMASK, V0 // mask out separator BLE CR4, index2to16 @@ -179,10 +170,10 @@ index2plus: // that value when found. Loop as // long as len(string) > 16 index2loop2: - VLOADSWAP(R7, R19, V3, V3_) // Load 16 bytes @R7+1 into V3 + VLOADSWAP(R7, R19, V3, V3) // Load 16 bytes @R7+1 into V3 index2loop: - VLOADSWAP(R7, R0, V2, V2_) // Load 16 bytes @R7 into V2 + VLOADSWAP(R7, R0, V2, V2) // Load 16 bytes @R7 into V2 VCMPEQUH V1, V2, V5 // Search for sep VCMPEQUH V1, V3, V6 // Search for sep offset by 1 VSEL V6, V5, V31, V7 // merge even and odd indices @@ -201,7 +192,7 @@ index2loop: BLT index2loop2 // If < last, continue loop CMP R7, LASTBYTE // Compare addr+16 against last byte BLT index2to16 // If < 16 handle specially - VLOADSWAP(R7, R0, V3, V3_) // Load 16 bytes @R7 into V3 + VLOADSWAP(R7, R0, V3, V3) // Load 16 bytes @R7 into V3 VSLDOI $1, V3, V10, V3 // Shift left by 1 byte BR index2loop @@ -234,11 +225,11 @@ index3plus: index3loop2: MOVD $2, R21 // Set up index for 2 VSPLTISB $0, V10 // Clear V10 - VLOADSWAP(R7, R21, V3, V3_)// Load 16 bytes @R7+2 into V3 + VLOADSWAP(R7, R21, V3, V3)// Load 16 bytes @R7+2 into V3 VSLDOI $14, V3, V10, V3 // Left justify next 2 bytes index3loop: - VLOADSWAP(R7, R0, V2, V2_) // Load with correct order + VLOADSWAP(R7, R0, V2, V2) // Load with correct order VSLDOI $1, V2, V3, V4 // string[1:17] VSLDOI $2, V2, V3, V9 // string[2:18] VCMPEQUH V1, V2, V5 // compare hw even indices @@ -294,12 +285,12 @@ index4plus: VSPLTW $0, V0, V1 // Splat 1st word of separator index4loop: - VLOADSWAP(R7, R0, V2, V2_) // Load 16 bytes @R7 into V2 + VLOADSWAP(R7, R0, V2, V2) // Load 16 bytes @R7 into V2 next4: VSPLTISB $0, V10 // Clear MOVD $3, R9 // Number of bytes beyond 16 - VLOADSWAP(R7, R9, V3, V3_) // Load 16 bytes @R7+3 into V3 + VLOADSWAP(R7, R9, V3, V3) // Load 16 bytes @R7+3 into V3 VSLDOI $13, V3, V10, V3 // Shift left last 3 bytes VSLDOI $1, V2, V3, V4 // V4=(V2:V3)<<1 VSLDOI $2, V2, V3, V9 // V9=(V2:V3)<<2 @@ -344,7 +335,7 @@ index2to16: // At least 16 bytes of string left // Mask the number of bytes in sep index2to16loop: - VLOADSWAP(R7, R0, V1, V1_) // Load 16 bytes @R7 into V1 + VLOADSWAP(R7, R0, V1, V1) // Load 16 bytes @R7 into V1 compare: VAND V1, SEPMASK, V2 // Mask out sep size @@ -366,14 +357,14 @@ index2to16tail: ADD R10, R9, R11 // offset + len CMP R11, $16 // >= 16? BLE short // Does not cross 16 bytes - VLOADSWAP(R7, R0, V1, V1_)// Load 16 bytes @R7 into V1 + VLOADSWAP(R7, R0, V1, V1) // Load 16 bytes @R7 into V1 BR index2to16next // Continue on short: RLDICR $0, R7, $59, R9 // Adjust addr to 16 byte container - VLOADSWAP(R9, R0, V1, V1_)// Load 16 bytes @R9 into V1 + VLOADSWAP(R9, R0, V1, V1)// Load 16 bytes @R9 into V1 SLD $3, R10 // Set up shift - MTVSRD R10, V8_ // Set up shift + MTVSRD R10, V8 // Set up shift VSLDOI $8, V8, V8, V8 VSLO V1, V8, V1 // Shift by start byte VSPLTISB $0, V25 // Clear for later use @@ -393,17 +384,17 @@ index17plus: BGT index33plus SUB $16, R6, R9 // Extra > 16 SLD $56, R9, R10 // Shift to use in VSLO - MTVSRD R10, V9_ // Set up for VSLO - VLOADSWAP(R5, R9, V1, V1_)// Load 16 bytes @R5+R9 into V1 + MTVSRD R10, V9 // Set up for VSLO + VLOADSWAP(R5, R9, V1, V1)// Load 16 bytes @R5+R9 into V1 VSLO V1, V9, V1 // Shift left VSPLTISB $0xff, V7 // Splat 1s VSPLTISB $0, V27 // Splat 0 index17to32loop: - VLOADSWAP(R7, R0, V2, V2_) // Load 16 bytes @R7 into V2 + VLOADSWAP(R7, R0, V2, V2) // Load 16 bytes @R7 into V2 next17: - VLOADSWAP(R7, R9, V3, V3_) // Load 16 bytes @R7+R9 into V3 + VLOADSWAP(R7, R9, V3, V3) // Load 16 bytes @R7+R9 into V3 VSLO V3, V9, V3 // Shift left VCMPEQUB V0, V2, V4 // Compare first 16 bytes VCMPEQUB V1, V3, V5 // Compare extra over 16 bytes @@ -454,7 +445,7 @@ TEXT indexbodyp9<>(SB), NOSPLIT|NOFRAME, $0 BGE CR4, loadge16 // Load for len(sep) >= 16 SUB R6, R16, R9 // 16-len of sep SLD $3, R9 // Set up for VSLO - MTVSRD R9, V9_ // Set up for VSLO + MTVSRD R9, V9 // Set up for VSLO VSLDOI $8, V9, V9, V9 // Set up for VSLO VSLO ONES, V9, SEPMASK // Mask for separator len(sep) < 16 @@ -465,9 +456,9 @@ loadge16: BGT sepcross16 // Sep crosses 16 byte boundary RLDICR $0, R5, $59, R8 // Adjust addr to 16 byte container - LXVB16X (R8)(R0), V0_ // Load 16 bytes @R8 into V0 + LXVB16X (R8)(R0), V0 // Load 16 bytes @R8 into V0 SLD $3, R9 // Set up shift count for VSLO - MTVSRD R9, V8_ // Set up shift count for VSLO + MTVSRD R9, V8 // Set up shift count for VSLO VSLDOI $8, V8, V8, V8 VSLO V0, V8, V0 // Shift by start byte @@ -475,7 +466,7 @@ loadge16: BR index2plus sepcross16: - LXVB16X (R5)(R0), V0_ // Load 16 bytes @R5 into V0 + LXVB16X (R5)(R0), V0 // Load 16 bytes @R5 into V0 VAND V0, SEPMASK, V0 // mask out separator BLE CR4, index2to16 @@ -504,10 +495,10 @@ index2plus: // that value when found. Loop as // long as len(string) > 16 index2loop2: - LXVB16X (R7)(R19), V3_ // Load 16 bytes @R7+1 into V3 + LXVB16X (R7)(R19), V3 // Load 16 bytes @R7+1 into V3 index2loop: - LXVB16X (R7)(R0), V2_ // Load 16 bytes @R7 into V2 + LXVB16X (R7)(R0), V2 // Load 16 bytes @R7 into V2 VCMPEQUH V1, V2, V5 // Search for sep VCMPEQUH V1, V3, V6 // Search for sep offset by 1 VSEL V6, V5, V31, V7 // merge even and odd indices @@ -526,7 +517,7 @@ index2loop: BLT index2loop2 // If < last, continue loop CMP R7, LASTBYTE // Compare addr+16 against last byte BLT index2to16 // If < 16 handle specially - LXVB16X (R7)(R0), V3_ // Load 16 bytes @R7 into V3 + LXVB16X (R7)(R0), V3 // Load 16 bytes @R7 into V3 VSLDOI $1, V3, V10, V3 // Shift left by 1 byte BR index2loop @@ -559,11 +550,11 @@ index3plus: index3loop2: MOVD $2, R21 // Set up index for 2 VSPLTISB $0, V10 // Clear V10 - LXVB16X (R7)(R21), V3_ // Load 16 bytes @R7+2 into V3 + LXVB16X (R7)(R21), V3 // Load 16 bytes @R7+2 into V3 VSLDOI $14, V3, V10, V3 // Left justify next 2 bytes index3loop: - LXVB16X (R7)(R0), V2_ // Load 16 bytes @R7 + LXVB16X (R7)(R0), V2 // Load 16 bytes @R7 VSLDOI $1, V2, V3, V4 // string[1:17] VSLDOI $2, V2, V3, V9 // string[2:18] VCMPEQUH V1, V2, V5 // compare hw even indices @@ -604,7 +595,6 @@ index4plus: ADD $20, R7, R9 // Check string size to load CMP R9, LASTBYTE // Verify string length BGE index2to16 // If not large enough, process remaining - MOVD $2, R15 // Set up index // Set up masks for use with VSEL MOVD $0xff, R21 // Set up mask 0xff000000ff000000... @@ -619,12 +609,12 @@ index4plus: VSPLTW $0, V0, V1 // Splat 1st word of separator index4loop: - LXVB16X (R7)(R0), V2_ // Load 16 bytes @R7 into V2 + LXVB16X (R7)(R0), V2 // Load 16 bytes @R7 into V2 next4: VSPLTISB $0, V10 // Clear MOVD $3, R9 // Number of bytes beyond 16 - LXVB16X (R7)(R9), V3_ // Load 16 bytes @R7 into V2 + LXVB16X (R7)(R9), V3 // Load 16 bytes @R7 into V2 VSLDOI $13, V3, V10, V3 // Shift left last 3 bytes VSLDOI $1, V2, V3, V4 // V4=(V2:V3)<<1 VSLDOI $2, V2, V3, V9 // V9=(V2:V3)<<2 @@ -662,46 +652,91 @@ index2to16: CMP R7, LASTSTR // Compare last start byte BGT notfound // last takes len(sep) into account - ADD $16, R7, R9 // Check for last byte of string + ADD $19, R7, R9 // To check 4 indices per iteration, need at least 16+3 bytes CMP R9, LASTBYTE BGT index2to16tail // At least 16 bytes of string left // Mask the number of bytes in sep -index2to16loop: - LXVB16X (R7)(R0), V1_ // Load 16 bytes @R7 into V1 + VSPLTISB $0, V10 // Clear + MOVD $3, R17 // Number of bytes beyond 16 -compare: - VAND V1, SEPMASK, V2 // Mask out sep size - VCMPEQUBCC V0, V2, V3 // Compare masked string - BLT CR6, found // All equal - ADD $1, R7 // Update ptr to next byte +index2to16loop: + LXVB16X (R7)(R0), V1 // Load next 16 bytes of string into V1 from R7 + LXVB16X (R7)(R17), V5 // Load next 16 bytes of string into V5 from R7+3 + + VSLDOI $13, V5, V10, V2 // Shift left last 3 bytes + VSLDOI $1, V1, V2, V3 // V3=(V1:V2)<<1 + VSLDOI $2, V1, V2, V4 // V4=(V1:V2)<<2 + VAND V1, SEPMASK, V8 // Mask out sep size 0th index + VAND V3, SEPMASK, V9 // Mask out sep size 1st index + VAND V4, SEPMASK, V11 // Mask out sep size 2nd index + VAND V5, SEPMASK, V12 // Mask out sep size 3rd index + VCMPEQUBCC V0, V8, V8 // compare masked string + BLT CR6, found // All equal while comparing 0th index + VCMPEQUBCC V0, V9, V9 // compare masked string + BLT CR6, found2 // All equal while comparing 1st index + VCMPEQUBCC V0, V11, V11 // compare masked string + BLT CR6, found3 // All equal while comparing 2nd index + VCMPEQUBCC V0, V12, V12 // compare masked string + BLT CR6, found4 // All equal while comparing 3rd index + + ADD $4, R7 // Update ptr to next 4 bytes CMP R7, LASTSTR // Still less than last start byte BGT notfound // Not found - ADD $16, R7, R9 // Verify remaining bytes - CMP R9, LASTBYTE // At least 16 - BLT index2to16loop // Try again + ADD $19, R7, R9 // Verify remaining bytes + CMP R9, LASTBYTE // length of string at least 19 + BLE index2to16loop // Try again, else do post processing and jump to index2to16next - // Less than 16 bytes remaining in string - // Separator >= 2 + // <19 bytes left, post process the remaining string index2to16tail: - ADD R3, R4, R9 // End of string - SUB R7, R9, R9 // Number of bytes left - ANDCC $15, R7, R10 // 16 byte offset - ADD R10, R9, R11 // offset + len - CMP R11, $16 // >= 16? - BLE short // Does not cross 16 bytes - LXVB16X (R7)(R0), V1_ // Load 16 bytes @R7 into V1 - BR index2to16next // Continue on + ADD R3, R4, R9 // End of string + SUB R7, R9, R9 // Number of bytes left + ANDCC $15, R7, R10 // 16 byte offset + ADD R10, R9, R11 // offset + len + CMP R11, $16 // >= 16? + BLE short // Does not cross 16 bytes + LXVB16X (R7)(R0), V1 // Load 16 bytes @R7 into V1 + CMP R9, $16 // Post-processing of unrolled loop + BLE index2to16next // continue to index2to16next if <= 16 bytes + SUB R16, R9, R10 // R9 should be 18 or 17 hence R10 is 1 or 2 + LXVB16X (R7)(R10), V9 + CMP R10, $1 // string length is 17, compare 1 more byte + BNE extra2 // string length is 18, compare 2 more bytes + VSLDOI $15, V9, V10, V25 + VAND V1, SEPMASK, V2 // Just compare size of sep + VCMPEQUBCC V0, V2, V3 // Compare sep and partial string + BLT CR6, found // Found + ADD $1, R7 // Not found, try next partial string + CMP R7, LASTSTR // Check for end of string + BGT notfound // If at end, then not found + VSLDOI $1, V1, V25, V1 // Shift string left by 1 byte + BR index2to16next // go to remainder loop +extra2: + VSLDOI $14, V9, V10, V25 + VAND V1, SEPMASK, V2 // Just compare size of sep + VCMPEQUBCC V0, V2, V3 // Compare sep and partial string + BLT CR6, found // Found + ADD $1, R7 // Not found, try next partial string + CMP R7, LASTSTR // Check for end of string + BGT notfound // If at end, then not found + VSLDOI $1, V1, V25, V1 // Shift string left by 1 byte + VAND V1, SEPMASK, V2 // Just compare size of sep + VCMPEQUBCC V0, V2, V3 // Compare sep and partial string + BLT CR6, found // Found + ADD $1, R7 // Not found, try next partial string + CMP R7, LASTSTR // Check for end of string + BGT notfound // If at end, then not found + VSLDOI $1, V1, V25, V1 // Shift string left by 1 byte + BR index2to16next // Check the remaining partial string in index2to16next short: - RLDICR $0, R7, $59, R9 // Adjust addr to 16 byte container - LXVB16X (R9)(R0), V1_ // Load 16 bytes @R9 into V1 - SLD $3, R10 // Set up shift - MTVSRD R10, V8_ // Set up shift + RLDICR $0, R7, $59, R9 // Adjust addr to 16 byte container + LXVB16X (R9)(R0), V1 // Load 16 bytes @R9 into V1 + SLD $3, R10 // Set up shift + MTVSRD R10, V8 // Set up shift VSLDOI $8, V8, V8, V8 - VSLO V1, V8, V1 // Shift by start byte - VSPLTISB $0, V25 // Clear for later use + VSLO V1, V8, V1 // Shift by start byte index2to16next: VAND V1, SEPMASK, V2 // Just compare size of sep @@ -710,7 +745,7 @@ index2to16next: ADD $1, R7 // Not found, try next partial string CMP R7, LASTSTR // Check for end of string BGT notfound // If at end, then not found - VSLDOI $1, V1, V25, V1 // Shift string left by 1 byte + VSLDOI $1, V1, V10, V1 // Shift string left by 1 byte BR index2to16next // Check the next partial string index17plus: @@ -718,17 +753,17 @@ index17plus: BGT index33plus SUB $16, R6, R9 // Extra > 16 SLD $56, R9, R10 // Shift to use in VSLO - MTVSRD R10, V9_ // Set up for VSLO - LXVB16X (R5)(R9), V1_ // Load 16 bytes @R5+R9 into V1 + MTVSRD R10, V9 // Set up for VSLO + LXVB16X (R5)(R9), V1 // Load 16 bytes @R5+R9 into V1 VSLO V1, V9, V1 // Shift left VSPLTISB $0xff, V7 // Splat 1s VSPLTISB $0, V27 // Splat 0 index17to32loop: - LXVB16X (R7)(R0), V2_ // Load 16 bytes @R7 into V2 + LXVB16X (R7)(R0), V2 // Load 16 bytes @R7 into V2 next17: - LXVB16X (R7)(R9), V3_ // Load 16 bytes @R7+R9 into V3 + LXVB16X (R7)(R9), V3 // Load 16 bytes @R7+R9 into V3 VSLO V3, V9, V3 // Shift left VCMPEQUB V0, V2, V4 // Compare first 16 bytes VCMPEQUB V1, V3, V5 // Compare extra over 16 bytes @@ -754,8 +789,13 @@ foundR25: SUB R3, R7 // Subtract from start of string MOVD R7, R3 // Return byte where found RET - -found: +found4: + ADD $1, R7 // found from unrolled loop at index 3 +found3: + ADD $1, R7 // found from unrolled loop at index 2 +found2: + ADD $1, R7 // found from unrolled loop at index 1 +found: // found at index 0 SUB R3, R7 // Return byte where found MOVD R7, R3 RET -- 2.48.1