From patchwork Tue Mar 21 20:11:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wainer dos Santos Moschetta X-Patchwork-Id: 19691 X-Patchwork-Delegate: tuliom@linux.vnet.ibm.com Received: (qmail 125758 invoked by alias); 21 Mar 2017 20:11:59 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 125745 invoked by uid 89); 21 Mar 2017 20:11:59 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-26.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_LAZY_DOMAIN_SECURITY, RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.2 spammy=Case, 58, deduct, allowable X-HELO: mx0a-001b2d01.pphosted.com From: Wainer dos Santos Moschetta To: libc-alpha@sourceware.org Subject: [PATCH] powerpc64: Add POWER8 strnlen Date: Tue, 21 Mar 2017 17:11:44 -0300 X-TM-AS-MML: disable x-cbid: 17032120-0020-0000-0000-00000296565E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032120-0021-0000-0000-000030B27C91 Message-Id: <20170321201144.10513-1-wainersm@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-21_17:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=4 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703210170 Added strnlen POWER8 otimized for long strings. It delivers same performance as POWER7 implementation for short strings. This takes advantage of reasonably performing unaligned loads and bit permutes to check the first 1-16 bytes until quadword aligned, then checks in 64 bytes strides until unsafe, then 16 bytes, truncating the count if need be. Likewise, the POWER7 code is recycled for less than 32 bytes strings. Tested on ppc64 and ppc64le. 2017-03-20 Wainer dos Santos Moschetta Paul E. Murphy * sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add strnlen-power8. * sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c (strnlen): Add __strnlen_power8 to list of strnlen functions. * sysdeps/powerpc/powerpc64/multiarch/strnlen-power8.S: New file. * sysdeps/powerpc/powerpc64/multiarch/strnlen.c (__strnlen): Add __strnlen_power8 to ifunc list. * sysdeps/powerpc/powerpc64/power8/strnlen.S: New file. --- sysdeps/powerpc/powerpc64/multiarch/Makefile | 5 +- .../powerpc/powerpc64/multiarch/ifunc-impl-list.c | 3 + .../powerpc/powerpc64/multiarch/strnlen-power8.S | 28 ++ sysdeps/powerpc/powerpc64/multiarch/strnlen.c | 9 +- sysdeps/powerpc/powerpc64/power8/strnlen.S | 433 +++++++++++++++++++++ 5 files changed, 473 insertions(+), 5 deletions(-) create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strnlen-power8.S create mode 100644 sysdeps/powerpc/powerpc64/power8/strnlen.S diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile index f5889a3..38233a7 100644 --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile @@ -5,8 +5,9 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \ memset-ppc64 memset-power8 \ mempcpy-power7 mempcpy-ppc64 memchr-power7 memchr-ppc64 \ memrchr-power7 memrchr-ppc64 rawmemchr-power7 \ - rawmemchr-ppc64 strlen-power7 strlen-ppc64 strnlen-power7 \ - strnlen-ppc64 strcasecmp-power7 strcasecmp_l-power7 \ + rawmemchr-ppc64 strlen-power7 strlen-ppc64 \ + strnlen-power8 strnlen-power7 strnlen-ppc64 \ + strcasecmp-power7 strcasecmp_l-power7 \ strncase-power7 strncase_l-power7 \ strncmp-power9 strncmp-power8 strncmp-power7 \ strncmp-power4 strncmp-ppc64 \ diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c index 209aec5..30a0133 100644 --- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c +++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c @@ -204,6 +204,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, /* Support sysdeps/powerpc/powerpc64/multiarch/strnlen.c. */ IFUNC_IMPL (i, name, strnlen, + IFUNC_IMPL_ADD (array, i, strnlen, + hwcap2 & PPC_FEATURE2_ARCH_2_07, + __strnlen_power8) IFUNC_IMPL_ADD (array, i, strnlen, hwcap & PPC_FEATURE_HAS_VSX, __strnlen_power7) IFUNC_IMPL_ADD (array, i, strnlen, 1, diff --git a/sysdeps/powerpc/powerpc64/multiarch/strnlen-power8.S b/sysdeps/powerpc/powerpc64/multiarch/strnlen-power8.S new file mode 100644 index 0000000..ccea15d --- /dev/null +++ b/sysdeps/powerpc/powerpc64/multiarch/strnlen-power8.S @@ -0,0 +1,28 @@ +/* Optimized strnlen version for POWER8. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +#define __strnlen __strnlen_power8 + +#undef libc_hidden_builtin_def +#define libc_hidden_builtin_def(name) +#undef weak_alias +#define weak_alias(name, alias) + +#include diff --git a/sysdeps/powerpc/powerpc64/multiarch/strnlen.c b/sysdeps/powerpc/powerpc64/multiarch/strnlen.c index 9854c18..7f89132 100644 --- a/sysdeps/powerpc/powerpc64/multiarch/strnlen.c +++ b/sysdeps/powerpc/powerpc64/multiarch/strnlen.c @@ -25,12 +25,15 @@ extern __typeof (__strnlen) __strnlen_ppc attribute_hidden; extern __typeof (__strnlen) __strnlen_power7 attribute_hidden; +extern __typeof (__strnlen) __strnlen_power8 attribute_hidden; # undef strnlen # undef __strnlen libc_ifunc_redirected (__redirect___strnlen, __strnlen, - (hwcap & PPC_FEATURE_HAS_VSX) - ? __strnlen_power7 - : __strnlen_ppc); + (hwcap2 & PPC_FEATURE2_ARCH_2_07) + ? __strnlen_power8 : + (hwcap & PPC_FEATURE_HAS_VSX) + ? __strnlen_power7 + : __strnlen_ppc); weak_alias (__strnlen, strnlen) #else diff --git a/sysdeps/powerpc/powerpc64/power8/strnlen.S b/sysdeps/powerpc/powerpc64/power8/strnlen.S new file mode 100644 index 0000000..3eadbfb --- /dev/null +++ b/sysdeps/powerpc/powerpc64/power8/strnlen.S @@ -0,0 +1,433 @@ +/* Optimized strnlen implementation for POWER8 using a vmx loop. + + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* It is implemented the following heuristic: + 1. Case maxlen <= 32: align the pointer to 8 bytes to loop through + reading doublewords. Uses the POWER7 algorithm. + 2. Case maxlen > 32: check for null bytes in the first 16 bytes using + unaligned accesses. Return length if found. Otherwise: + 2.1 Case maxlen < 64: deduct the bytes previously read, align + the pointer to 16 bytes and loop through reading quadwords + until find null bytes or reach maxlen. + 2.2 Case maxlen > 64: deduct the bytes previously read, align + the pointer to 64 bytes and set up a counter to loop through + reading in strides of 64 bytes. In case it finished the loop + with null bytes not found, process the remainder bytes by + switching to the loop to heuristic in 2.1. */ + +#include + +/* Define default page size to 4KB. */ +#define PAGE_SIZE 4096 + +/* The following macros implement Power ISA v2.07 opcodes + that could not be used directly into this code to the keep + compatibility with older binutils versions. */ + +/* Move from vector register doubleword. */ +#define MFVRD(r,v) .long (0x7c000067 | ((v)<<(32-11)) | ((r)<<(32-16))) + +/* Move to vector register doubleword. */ +#define MTVRD(v,r) .long (0x7c000167 | ((v)<<(32-11)) | ((r)<<(32-16))) + +/* Vector Bit Permute Quadword. */ +#define VBPERMQ(t,a,b) .long (0x1000054c \ + | ((t)<<(32-11)) \ + | ((a)<<(32-16)) \ + | ((b)<<(32-21)) ) + +/* Vector Population Count Halfword. */ +#define VPOPCNTH(t,b) .long (0x10000743 | ((t)<<(32-11)) | ((b)<<(32-21))) + +/* Vector Count Leading Zeros Halfword. */ +#define VCLZH(t,b) .long (0x10000742 | ((t)<<(32-11)) | ((b)<<(32-21))) + + +/* int [r3] strnlen (char *s [r3], size_t maxlen [r4]) */ +/* TODO: change to power8 when minimum required binutils allows it. */ + .machine power7 +ENTRY (__strnlen) + CALL_MCOUNT 2 + dcbt 0,r3 + + cmpldi r4,32 /* Check if maxlen <= 32. */ + ble L(small_range) /* If maxlen <= 32. */ + + /* Upcoming 16 bytes unaligned accesses cannot cross the page boundary + otherwise the processor throws an memory access error. + Use following code to check there is room for such as accesses: + (((size_t) s) % PAGE_SIZE > (PAGE_SIZE - 16) + If it is disallowed then switch to the code that handles + the string when maxlen <= 32. */ + clrldi r10,r3,52 + cmpldi cr7,r10,PAGE_SIZE-16 + bgt cr7,L(small_range) /* If less than 16B of page end. */ + + /* Compute our permute constant r8. */ + li r7,0 + /* Compute a bpermd constant to move bit 0 of each word into + a halfword value, and count trailing zeros. */ +#ifdef __LITTLE_ENDIAN__ + li r8,0x2820 + oris r8,r8,0x3830 + sldi r8,r8,32 + ori r8,r8,0x0800 + oris r8,r8,0x1810 +#else + li r8,0x1018 + oris r8,r8,0x0008 + sldi r8,r8,32 + ori r8,r8,0x3038 + oris r8,r8,0x2028 +#endif + + /* maxlen > 32. Optimistically check for null bytes in the first + 16 bytes of the string using unaligned accesses. */ + ld r5,0(r3) + ld r6,8(r3) + cmpb r10,r7,r5 /* Check for null bytes in DWORD1. */ + cmpb r11,r7,r6 /* Check for null bytes in DWORD2. */ + or. r7,r10,r11 + bne cr0, L(early_find) /* If found null bytes. */ + + /* At this point maxlen > 32 and null bytes were not found at first + 16 bytes. Prepare for loop using VMX. */ + + /* r3 == s, r4 == maxlen. All other volatile regs are unused now. */ + + addi r5,r3,16 /* Align up, or just add the 16B we + already checked. */ + li r0,15 + and r7,r5,r0 /* Find offset into 16B alignment. */ + andc r5,r5,r0 /* Quadword align up s to the next quadword. */ + li r0,16 + subf r0,r7,r0 + subf r4,r0,r4 /* Deduct unaligned bytes from maxlen. */ + + + /* Compute offsets for vmx loads, and precompute the vbpermq + constants for both the 64B and 16B loops. */ + li r6,0 + vspltisb v0,0 + vspltisb v10,3 + lvsl v11,r6,r6 + vslb v10,v11,v10 + + cmpldi r4,64 /* Check maxlen < 64. */ + blt L(smaller) /* If maxlen < 64 */ + + /* In order to begin the 64B loop, it needs to be 64 + bytes aligned. So read quadwords until it is aligned or found null + bytes. At worst case it will be aligned after the fourth iteration, + so unroll the loop to avoid counter checking. */ + andi. r7,r5,63 /* Check if is 64 bytes aligned. */ + beq cr0,L(preloop_64B) /* If it is already 64B aligned. */ + lvx v1,r5,r6 + vcmpequb. v1,v1,v0 + addi r5,r5,16 + addi r4,r4,-16 /* Decrement maxlen in 16 bytes. */ + bne cr6,L(found_aligning64B) /* If found null bytes. */ + + /* Unroll 3x above code block until aligned or find null bytes. */ + andi. r7,r5,63 + beq cr0,L(preloop_64B) + lvx v1,r5,r6 + vcmpequb. v1,v1,v0 + addi r5,r5,16 + addi r4,r4,-16 + bne cr6,L(found_aligning64B) + + andi. r7,r5,63 + beq cr0,L(preloop_64B) + lvx v1,r5,r6 + vcmpequb. v1,v1,v0 + addi r5,r5,16 + addi r4,r4,-16 + bne cr6,L(found_aligning64B) + + andi. r7,r5,63 + beq cr0,L(preloop_64B) + lvx v1,r5,r6 + vcmpequb. v1,v1,v0 + addi r5,r5,16 + addi r4,r4,-16 + bne cr6,L(found_aligning64B) + + /* At this point it should be 16 bytes aligned. + Prepare for the 64B loop. */ + .p2align 4 +L(preloop_64B): + /* Check if maxlen became is less than 64, therefore disallowing the + 64B loop. If it happened switch to the 16B loop code. */ + cmpldi r4,64 /* Check if maxlen < 64. */ + blt L(smaller) /* If maxlen < 64. */ + /* Set some constant values. */ + li r7,16 + li r10,32 + li r9,48 + + /* Compute the number of 64 bytes iterations needed. */ + srdi r11,r4,6 /* Compute loop count (maxlen / 64). */ + andi. r4,r4,63 /* Set maxlen the remainder (maxlen % 64). */ + mtctr r11 /* Move loop count to counter register. */ + + /* Handle maxlen > 64. Loop over the bytes in strides of 64B. */ + .p2align 4 +L(loop_64B): + lvx v1,r5,r6 /* r5 is the pointer to s. */ + lvx v2,r5,r7 + lvx v3,r5,r10 + lvx v4,r5,r9 + /* Compare the four 16B vectors to obtain the least 16 values. + Null bytes should emerge into v7, then check for null bytes. */ + vminub v5,v1,v2 + vminub v6,v3,v4 + vminub v7,v5,v6 + vcmpequb. v7,v7,v0 /* Check for null bytes. */ + addi r5,r5,64 /* Add pointer to next iteraction. */ + bne cr6,L(found_64B) /* If found null bytes. */ + bdnz L(loop_64B) /* Continue the loop if count > 0. */ + +/* Hit loop end without null match. So branch to handle the remainder. */ + + /* Prepare a 16B loop to handle two cases: + 1. If 32 > maxlen < 64. + 2. If maxlen >= 64, and reached end of the 64B loop with null + bytes not found. Thus handle the remainder bytes here. */ + .p2align 4 +L(smaller): + cmpldi r4,0 /* Check maxlen is zero. */ + beq L(done) /* If maxlen is zero. */ + + /* Place rounded up number of qw's to check into a vmx + register, and use some vector tricks to minimize + branching. */ + MTVRD(v7,r4) /* Copy maxlen from GPR to vector register. */ + vspltisb v5,1 + vspltisb v6,15 + vspltb v2,v7,7 + vaddubs v3,v5,v6 + +#ifdef __LITTLE_ENDIAN__ + vspltish v5,1 /* Compute 16 in each byte. */ +#endif + + /* Loop in 16B aligned incremements now. */ + .p2align 4 +L(loop_16B): + lvx v1,r5,r6 /* Load quadword into vector register. */ + addi r5,r5,16 /* Increment address to next 16B block. */ + vor v7,v2,v2 /* Save loop count (v2) into v7. */ + vsububs v2,v2,v3 /* Subtract 16B from count, saturate at 0. */ + vminub v4,v1,v2 + vcmpequb. v4,v4,v0 /* Checking for null bytes. */ + beq cr6,L(loop_16B) /* If null bytes not found. */ + + vcmpequb v1,v1,v0 + VBPERMQ(v1,v1,v10) +#ifdef __LITTLE_ENDIAN__ + vsubuhm v2,v1,v5 /* Form a mask of trailing zeros. */ + vandc v2,v2,v1 + VPOPCNTH(v1,v2) /* Count of trailing zeros, 16 if none. */ +#else + VCLZH(v1,v1) /* Count the leading zeros, 16 if none. */ +#endif + /* Truncate to maximum allowable offset. */ + vcmpgtub v2,v1,v7 /* Compare and truncate for matches beyond + maxlen. */ + vsel v1,v1,v7,v2 /* 0-16 is now in byte 7. */ + + MFVRD(r0,v1) + addi r5,r5,-16 /* Undo speculative bump. */ + extsb r0,r0 /* Clear whatever gunk is in the high 56b. */ + add r5,r5,r0 /* Add the offset of whatever was found. */ +L(done): + subf r3,r3,r5 /* Length is equal to the offset of null byte + matched minus the pointer to s. */ + blr /* Done. */ + + /* Handle case of maxlen > 64 and found null bytes in last block + of 64 bytes read. */ + .p2align 4 +L(found_64B): + /* A zero was found. Reduce the result. */ + vcmpequb v1,v1,v0 + vcmpequb v2,v2,v0 + vcmpequb v3,v3,v0 + vcmpequb v4,v4,v0 + + /* Permute the first bit of each byte into bits 48-63. */ + VBPERMQ(v1,v1,v10) + VBPERMQ(v2,v2,v10) + VBPERMQ(v3,v3,v10) + VBPERMQ(v4,v4,v10) + + /* Shift each component into its correct position for merging. */ +#ifdef __LITTLE_ENDIAN__ + vsldoi v2,v2,v2,2 + vsldoi v3,v3,v3,4 + vsldoi v4,v4,v4,6 +#else + vsldoi v1,v1,v1,6 + vsldoi v2,v2,v2,4 + vsldoi v3,v3,v3,2 +#endif + + /* Merge the results and move to a GPR. */ + vor v1,v2,v1 + vor v2,v3,v4 + vor v4,v1,v2 + + /* Adjust address to the start of the current 64B block. */ + addi r5,r5,-64 + + MFVRD(r10,v4) +#ifdef __LITTLE_ENDIAN__ + addi r9,r10,-1 /* Form a mask from trailing zeros. */ + andc r9,r9,r10 + popcntd r0,r9 /* Count the bits in the mask. */ +#else + cntlzd r0,r10 /* Count leading zeros before the match. */ +#endif + subf r5,r3,r5 + add r3,r5,r0 /* Compute final length. */ + blr /* Done. */ + + /* Handle case where null bytes were found while aligning + as a preparation for the 64B loop. */ + .p2align 4 +L(found_aligning64B): + VBPERMQ(v1,v1,v10) +#ifdef __LITTLE_ENDIAN__ + MFVRD(r10,v1) + addi r9,r10,-1 /* Form a mask from trailing zeros. */ + andc r9,r9,r10 + popcntd r0,r9 /* Count the bits in the mask. */ +#else + vsldoi v1,v1,v1,6 + MFVRD(r10,v1) + cntlzd r0,r10 /* Count leading zeros before the match. */ +#endif + addi r5,r5,-16 /* Adjust address to offset of last 16 bytes + read. */ + /* Calculate length as subtracted the pointer to s of last 16 bytes + offset, added with the bytes before the match. */ + subf r5,r3,r5 + add r3,r5,r0 + blr /* Done. */ + + /* Handle case of maxlen > 32 and found a null bytes within the first + 16 bytes of s. */ + .p2align 4 +L(early_find): + bpermd r5,r8,r10 /* r8 contains the bit permute constants. */ + bpermd r6,r8,r11 + sldi r5,r5,8 + or r5,r5,r6 /* r5 should hold a 16B mask of + a potential 0. */ + cntlzd r5,r5 /* Count leading zeros. */ + addi r3,r5,-48 /* Deduct the 48 leading zeros always + present. */ + blr /* Done. */ + + /* Handle case of maxlen <= 32. Use the POWER7 algorithm. */ + .p2align 4 +L(small_range): + clrrdi r8,r3,3 /* Align the pointer to 8B. */ + li r0,0 + /* Register's content at this point: + r3 == pointer to s, r4 == maxlen, r8 == pointer to s aligned to 8B, + r7 == last acceptable address. */ + cmpldi r4,0 /* Check if maxlen is zero. */ + beq L(end_max) /* If maxlen is zero. */ + + /* Calculate the last acceptable address and check for possible + addition overflow by using satured math: + r7 = r3 + r4 + r7 |= -(r7 < x) */ + add r7,r3,r4 + subfc r6,r3,r7 + subfe r9,r9,r9 + extsw r6,r9 + or r7,r7,r6 + addi r7,r7,-1 + + clrrdi r7,r7,3 /* Align to 8B address of last + acceptable address. */ + + rlwinm r6,r3,3,26,28 /* Calculate padding. */ + ld r12,0(r8) /* Load aligned doubleword. */ + cmpb r10,r12,r0 /* Check for null bytes. */ +#ifdef __LITTLE_ENDIAN__ + srd r10,r10,r6 + sld r10,r10,r6 +#else + sld r10,r10,r6 + srd r10,r10,r6 +#endif /* __LITTLE_ENDIAN__ */ + cmpldi cr7,r10,0 + bne cr7,L(done_small) /* If found null byte. */ + + cmpld r8,r7 /* Check if reached maxlen. */ + beq L(end_max) /* If reached maxlen. */ + + /* Still handling case of maxlen <= 32. Read doubleword aligned until + find null bytes or reach maxlen. */ + .p2align 4 +L(loop_small): + ldu r12,8(r8) /* Load next doubleword and update r8. */ + cmpb r10,r12,r0 /* Check for null bytes. */ + cmpldi cr6,r10,0 + bne cr6,L(done_small) /* If found null bytes. */ + cmpld r8,r7 /* Check if reached maxlen. */ + bne L(loop_small) /* If it has more bytes to read. */ + mr r3,r4 /* Reached maxlen with null bytes not found. + Length is equal to maxlen. */ + blr /* Done. */ + + /* Still handling case of maxlen <= 32. Found null bytes. + Registers: r10 == match bits within doubleword, r8 == address of + last doubleword read, r3 == pointer to s, r4 == maxlen. */ + .p2align 4 +L(done_small): +#ifdef __LITTLE_ENDIAN__ + /* Count trailing zeros. */ + addi r0,r10,-1 + andc r0,r0,r10 + popcntd r0,r0 +#else + cntlzd r0,r10 /* Count leading zeros before the match. */ +#endif + sub r3,r8,r3 /* Calculate total of bytes before the match. */ + srdi r0,r0,3 /* Convert leading/trailing zeros to bytes. */ + add r3,r3,r0 /* Length until the match. */ + cmpld r3,r4 /* Check length is greater than maxlen. */ + blelr + mr r3,r4 /* If length is greater than maxlen, return + maxlen. */ + blr + + /* Handle case of reached maxlen with null bytes not found. */ + .p2align 4 +L(end_max): + mr r3,r4 /* Length is equal to maxlen. */ + blr /* Done. */ + + +END (__strnlen) +libc_hidden_def (__strnlen) +weak_alias (__strnlen, strnlen) +libc_hidden_def (strnlen)