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glibc/SOURCES/glibc-RHEL-15696-31.patch

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import UBI glibc-2.28-251.el8_10.1
2024-05-22 13:49:58 +00:00
From 4ba65586847751372520a36757c17f114588794e Mon Sep 17 00:00:00 2001
From: Noah Goldstein <goldstein.w.n@gmail.com>
Date: Mon, 19 Apr 2021 19:36:06 -0400
Subject: [PATCH] x86: Optimize strlen-evex.S
Content-type: text/plain; charset=UTF-8
No bug. This commit optimizes strlen-evex.S. The
optimizations are mostly small things but they add up to roughly
10-30% performance improvement for strlen. The results for strnlen are
bit more ambiguous. test-strlen, test-strnlen, test-wcslen, and
test-wcsnlen are all passing.
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
---
sysdeps/x86_64/multiarch/strlen-evex.S | 581 ++++++++++++++-----------
1 file changed, 317 insertions(+), 264 deletions(-)
diff --git a/sysdeps/x86_64/multiarch/strlen-evex.S b/sysdeps/x86_64/multiarch/strlen-evex.S
index 05838190..4bf6874b 100644
--- a/sysdeps/x86_64/multiarch/strlen-evex.S
+++ b/sysdeps/x86_64/multiarch/strlen-evex.S
@@ -29,11 +29,13 @@
# ifdef USE_AS_WCSLEN
# define VPCMP vpcmpd
# define VPMINU vpminud
-# define SHIFT_REG r9d
+# define SHIFT_REG ecx
+# define CHAR_SIZE 4
# else
# define VPCMP vpcmpb
# define VPMINU vpminub
-# define SHIFT_REG ecx
+# define SHIFT_REG edx
+# define CHAR_SIZE 1
# endif
# define XMMZERO xmm16
@@ -46,132 +48,165 @@
# define YMM6 ymm22
# define VEC_SIZE 32
+# define PAGE_SIZE 4096
+# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
.section .text.evex,"ax",@progbits
ENTRY (STRLEN)
# ifdef USE_AS_STRNLEN
- /* Check for zero length. */
+ /* Check zero length. */
test %RSI_LP, %RSI_LP
jz L(zero)
-# ifdef USE_AS_WCSLEN
- shl $2, %RSI_LP
-# elif defined __ILP32__
+# ifdef __ILP32__
/* Clear the upper 32 bits. */
movl %esi, %esi
# endif
mov %RSI_LP, %R8_LP
# endif
- movl %edi, %ecx
- movq %rdi, %rdx
+ movl %edi, %eax
vpxorq %XMMZERO, %XMMZERO, %XMMZERO
-
+ /* Clear high bits from edi. Only keeping bits relevant to page
+ cross check. */
+ andl $(PAGE_SIZE - 1), %eax
/* Check if we may cross page boundary with one vector load. */
- andl $(2 * VEC_SIZE - 1), %ecx
- cmpl $VEC_SIZE, %ecx
- ja L(cros_page_boundary)
+ cmpl $(PAGE_SIZE - VEC_SIZE), %eax
+ ja L(cross_page_boundary)
/* Check the first VEC_SIZE bytes. Each bit in K0 represents a
null byte. */
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
- testl %eax, %eax
-
# ifdef USE_AS_STRNLEN
- jnz L(first_vec_x0_check)
- /* Adjust length and check the end of data. */
- subq $VEC_SIZE, %rsi
- jbe L(max)
-# else
- jnz L(first_vec_x0)
+ /* If length < CHAR_PER_VEC handle special. */
+ cmpq $CHAR_PER_VEC, %rsi
+ jbe L(first_vec_x0)
# endif
-
- /* Align data for aligned loads in the loop. */
- addq $VEC_SIZE, %rdi
- andl $(VEC_SIZE - 1), %ecx
- andq $-VEC_SIZE, %rdi
-
+ testl %eax, %eax
+ jz L(aligned_more)
+ tzcntl %eax, %eax
+ ret
# ifdef USE_AS_STRNLEN
- /* Adjust length. */
- addq %rcx, %rsi
+L(zero):
+ xorl %eax, %eax
+ ret
- subq $(VEC_SIZE * 4), %rsi
- jbe L(last_4x_vec_or_less)
+ .p2align 4
+L(first_vec_x0):
+ /* Set bit for max len so that tzcnt will return min of max len
+ and position of first match. */
+ btsq %rsi, %rax
+ tzcntl %eax, %eax
+ ret
# endif
- jmp L(more_4x_vec)
.p2align 4
-L(cros_page_boundary):
- andl $(VEC_SIZE - 1), %ecx
- andq $-VEC_SIZE, %rdi
-
-# ifdef USE_AS_WCSLEN
- /* NB: Divide shift count by 4 since each bit in K0 represent 4
- bytes. */
- movl %ecx, %SHIFT_REG
- sarl $2, %SHIFT_REG
+L(first_vec_x1):
+ tzcntl %eax, %eax
+ /* Safe to use 32 bit instructions as these are only called for
+ size = [1, 159]. */
+# ifdef USE_AS_STRNLEN
+ /* Use ecx which was computed earlier to compute correct value.
+ */
+ leal -(CHAR_PER_VEC * 4 + 1)(%rcx, %rax), %eax
+# else
+ subl %edx, %edi
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %edi
+# endif
+ leal CHAR_PER_VEC(%rdi, %rax), %eax
# endif
- VPCMP $0, (%rdi), %YMMZERO, %k0
- kmovd %k0, %eax
+ ret
- /* Remove the leading bytes. */
- sarxl %SHIFT_REG, %eax, %eax
- testl %eax, %eax
- jz L(aligned_more)
+ .p2align 4
+L(first_vec_x2):
tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
+ /* Safe to use 32 bit instructions as these are only called for
+ size = [1, 159]. */
# ifdef USE_AS_STRNLEN
- /* Check the end of data. */
- cmpq %rax, %rsi
- jbe L(max)
-# endif
- addq %rdi, %rax
- addq %rcx, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* Use ecx which was computed earlier to compute correct value.
+ */
+ leal -(CHAR_PER_VEC * 3 + 1)(%rcx, %rax), %eax
+# else
+ subl %edx, %edi
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %edi
+# endif
+ leal (CHAR_PER_VEC * 2)(%rdi, %rax), %eax
# endif
ret
.p2align 4
-L(aligned_more):
+L(first_vec_x3):
+ tzcntl %eax, %eax
+ /* Safe to use 32 bit instructions as these are only called for
+ size = [1, 159]. */
# ifdef USE_AS_STRNLEN
- /* "rcx" is less than VEC_SIZE. Calculate "rdx + rcx - VEC_SIZE"
- with "rdx - (VEC_SIZE - rcx)" instead of "(rdx + rcx) - VEC_SIZE"
- to void possible addition overflow. */
- negq %rcx
- addq $VEC_SIZE, %rcx
-
- /* Check the end of data. */
- subq %rcx, %rsi
- jbe L(max)
+ /* Use ecx which was computed earlier to compute correct value.
+ */
+ leal -(CHAR_PER_VEC * 2 + 1)(%rcx, %rax), %eax
+# else
+ subl %edx, %edi
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %edi
+# endif
+ leal (CHAR_PER_VEC * 3)(%rdi, %rax), %eax
# endif
+ ret
- addq $VEC_SIZE, %rdi
-
+ .p2align 4
+L(first_vec_x4):
+ tzcntl %eax, %eax
+ /* Safe to use 32 bit instructions as these are only called for
+ size = [1, 159]. */
# ifdef USE_AS_STRNLEN
- subq $(VEC_SIZE * 4), %rsi
- jbe L(last_4x_vec_or_less)
+ /* Use ecx which was computed earlier to compute correct value.
+ */
+ leal -(CHAR_PER_VEC + 1)(%rcx, %rax), %eax
+# else
+ subl %edx, %edi
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %edi
+# endif
+ leal (CHAR_PER_VEC * 4)(%rdi, %rax), %eax
# endif
+ ret
-L(more_4x_vec):
+ .p2align 5
+L(aligned_more):
+ movq %rdi, %rdx
+ /* Align data to VEC_SIZE. */
+ andq $-(VEC_SIZE), %rdi
+L(cross_page_continue):
/* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
since data is only aligned to VEC_SIZE. */
- VPCMP $0, (%rdi), %YMMZERO, %k0
- kmovd %k0, %eax
- testl %eax, %eax
- jnz L(first_vec_x0)
-
+# ifdef USE_AS_STRNLEN
+ /* + CHAR_SIZE because it simplies the logic in
+ last_4x_vec_or_less. */
+ leaq (VEC_SIZE * 5 + CHAR_SIZE)(%rdi), %rcx
+ subq %rdx, %rcx
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %ecx
+# endif
+# endif
+ /* Load first VEC regardless. */
VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
+# ifdef USE_AS_STRNLEN
+ /* Adjust length. If near end handle specially. */
+ subq %rcx, %rsi
+ jb L(last_4x_vec_or_less)
+# endif
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x1)
VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
- testl %eax, %eax
+ test %eax, %eax
jnz L(first_vec_x2)
VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0
@@ -179,258 +214,276 @@ L(more_4x_vec):
testl %eax, %eax
jnz L(first_vec_x3)
- addq $(VEC_SIZE * 4), %rdi
-
-# ifdef USE_AS_STRNLEN
- subq $(VEC_SIZE * 4), %rsi
- jbe L(last_4x_vec_or_less)
-# endif
-
- /* Align data to 4 * VEC_SIZE. */
- movq %rdi, %rcx
- andl $(4 * VEC_SIZE - 1), %ecx
- andq $-(4 * VEC_SIZE), %rdi
+ VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMZERO, %k0
+ kmovd %k0, %eax
+ testl %eax, %eax
+ jnz L(first_vec_x4)
+ addq $VEC_SIZE, %rdi
# ifdef USE_AS_STRNLEN
- /* Adjust length. */
+ /* Check if at last VEC_SIZE * 4 length. */
+ cmpq $(CHAR_PER_VEC * 4 - 1), %rsi
+ jbe L(last_4x_vec_or_less_load)
+ movl %edi, %ecx
+ andl $(VEC_SIZE * 4 - 1), %ecx
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarl $2, %ecx
+# endif
+ /* Readjust length. */
addq %rcx, %rsi
# endif
+ /* Align data to VEC_SIZE * 4. */
+ andq $-(VEC_SIZE * 4), %rdi
+ /* Compare 4 * VEC at a time forward. */
.p2align 4
L(loop_4x_vec):
- /* Compare 4 * VEC at a time forward. */
- VMOVA (%rdi), %YMM1
- VMOVA VEC_SIZE(%rdi), %YMM2
- VMOVA (VEC_SIZE * 2)(%rdi), %YMM3
- VMOVA (VEC_SIZE * 3)(%rdi), %YMM4
-
- VPMINU %YMM1, %YMM2, %YMM5
- VPMINU %YMM3, %YMM4, %YMM6
+ /* Load first VEC regardless. */
+ VMOVA (VEC_SIZE * 4)(%rdi), %YMM1
+# ifdef USE_AS_STRNLEN
+ /* Break if at end of length. */
+ subq $(CHAR_PER_VEC * 4), %rsi
+ jb L(last_4x_vec_or_less_cmpeq)
+# endif
+ /* Save some code size by microfusing VPMINU with the load. Since
+ the matches in ymm2/ymm4 can only be returned if there where no
+ matches in ymm1/ymm3 respectively there is no issue with overlap.
+ */
+ VPMINU (VEC_SIZE * 5)(%rdi), %YMM1, %YMM2
+ VMOVA (VEC_SIZE * 6)(%rdi), %YMM3
+ VPMINU (VEC_SIZE * 7)(%rdi), %YMM3, %YMM4
+
+ VPCMP $0, %YMM2, %YMMZERO, %k0
+ VPCMP $0, %YMM4, %YMMZERO, %k1
+ subq $-(VEC_SIZE * 4), %rdi
+ kortestd %k0, %k1
+ jz L(loop_4x_vec)
+
+ /* Check if end was in first half. */
+ kmovd %k0, %eax
+ subq %rdx, %rdi
+# ifdef USE_AS_WCSLEN
+ shrq $2, %rdi
+# endif
+ testl %eax, %eax
+ jz L(second_vec_return)
- VPMINU %YMM5, %YMM6, %YMM5
- VPCMP $0, %YMM5, %YMMZERO, %k0
- ktestd %k0, %k0
- jnz L(4x_vec_end)
+ VPCMP $0, %YMM1, %YMMZERO, %k2
+ kmovd %k2, %edx
+ /* Combine VEC1 matches (edx) with VEC2 matches (eax). */
+# ifdef USE_AS_WCSLEN
+ sall $CHAR_PER_VEC, %eax
+ orl %edx, %eax
+ tzcntl %eax, %eax
+# else
+ salq $CHAR_PER_VEC, %rax
+ orq %rdx, %rax
+ tzcntq %rax, %rax
+# endif
+ addq %rdi, %rax
+ ret
- addq $(VEC_SIZE * 4), %rdi
-# ifndef USE_AS_STRNLEN
- jmp L(loop_4x_vec)
-# else
- subq $(VEC_SIZE * 4), %rsi
- ja L(loop_4x_vec)
+# ifdef USE_AS_STRNLEN
+L(last_4x_vec_or_less_load):
+ /* Depending on entry adjust rdi / prepare first VEC in YMM1. */
+ VMOVA (VEC_SIZE * 4)(%rdi), %YMM1
+L(last_4x_vec_or_less_cmpeq):
+ VPCMP $0, %YMM1, %YMMZERO, %k0
+ addq $(VEC_SIZE * 3), %rdi
L(last_4x_vec_or_less):
- /* Less than 4 * VEC and aligned to VEC_SIZE. */
- addl $(VEC_SIZE * 2), %esi
- jle L(last_2x_vec)
-
- VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
+ /* If remaining length > VEC_SIZE * 2. This works if esi is off by
+ VEC_SIZE * 4. */
+ testl $(CHAR_PER_VEC * 2), %esi
+ jnz L(last_4x_vec)
+
+ /* length may have been negative or positive by an offset of
+ CHAR_PER_VEC * 4 depending on where this was called from. This
+ fixes that. */
+ andl $(CHAR_PER_VEC * 4 - 1), %esi
testl %eax, %eax
- jnz L(first_vec_x0)
+ jnz L(last_vec_x1_check)
- VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
- kmovd %k0, %eax
- testl %eax, %eax
- jnz L(first_vec_x1)
+ /* Check the end of data. */
+ subl $CHAR_PER_VEC, %esi
+ jb L(max)
VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
- testl %eax, %eax
- jnz L(first_vec_x2_check)
- subl $VEC_SIZE, %esi
- jle L(max)
+ tzcntl %eax, %eax
+ /* Check the end of data. */
+ cmpl %eax, %esi
+ jb L(max)
- VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0
- kmovd %k0, %eax
- testl %eax, %eax
- jnz L(first_vec_x3_check)
+ subq %rdx, %rdi
+# ifdef USE_AS_WCSLEN
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
+# endif
+ leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax
+ ret
+L(max):
movq %r8, %rax
+ ret
+# endif
+
+ /* Placed here in strnlen so that the jcc L(last_4x_vec_or_less)
+ in the 4x VEC loop can use 2 byte encoding. */
+ .p2align 4
+L(second_vec_return):
+ VPCMP $0, %YMM3, %YMMZERO, %k0
+ /* Combine YMM3 matches (k0) with YMM4 matches (k1). */
+# ifdef USE_AS_WCSLEN
+ kunpckbw %k0, %k1, %k0
+ kmovd %k0, %eax
+ tzcntl %eax, %eax
+# else
+ kunpckdq %k0, %k1, %k0
+ kmovq %k0, %rax
+ tzcntq %rax, %rax
+# endif
+ leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax
+ ret
+
+
+# ifdef USE_AS_STRNLEN
+L(last_vec_x1_check):
+ tzcntl %eax, %eax
+ /* Check the end of data. */
+ cmpl %eax, %esi
+ jb L(max)
+ subq %rdx, %rdi
# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
# endif
+ leaq (CHAR_PER_VEC)(%rdi, %rax), %rax
ret
.p2align 4
-L(last_2x_vec):
- addl $(VEC_SIZE * 2), %esi
+L(last_4x_vec):
+ /* Test first 2x VEC normally. */
+ testl %eax, %eax
+ jnz L(last_vec_x1)
- VPCMP $0, (%rdi), %YMMZERO, %k0
+ VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
- jnz L(first_vec_x0_check)
- subl $VEC_SIZE, %esi
- jle L(max)
+ jnz L(last_vec_x2)
- VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
+ /* Normalize length. */
+ andl $(CHAR_PER_VEC * 4 - 1), %esi
+ VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
- jnz L(first_vec_x1_check)
- movq %r8, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
-# endif
- ret
+ jnz L(last_vec_x3)
- .p2align 4
-L(first_vec_x0_check):
+ /* Check the end of data. */
+ subl $(CHAR_PER_VEC * 3), %esi
+ jb L(max)
+
+ VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMZERO, %k0
+ kmovd %k0, %eax
tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
/* Check the end of data. */
- cmpq %rax, %rsi
- jbe L(max)
- addq %rdi, %rax
- subq %rdx, %rax
+ cmpl %eax, %esi
+ jb L(max_end)
+
+ subq %rdx, %rdi
# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
# endif
+ leaq (CHAR_PER_VEC * 4)(%rdi, %rax), %rax
ret
.p2align 4
-L(first_vec_x1_check):
+L(last_vec_x1):
tzcntl %eax, %eax
+ subq %rdx, %rdi
# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- /* Check the end of data. */
- cmpq %rax, %rsi
- jbe L(max)
- addq $VEC_SIZE, %rax
- addq %rdi, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
# endif
+ leaq (CHAR_PER_VEC)(%rdi, %rax), %rax
ret
.p2align 4
-L(first_vec_x2_check):
+L(last_vec_x2):
tzcntl %eax, %eax
+ subq %rdx, %rdi
# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- /* Check the end of data. */
- cmpq %rax, %rsi
- jbe L(max)
- addq $(VEC_SIZE * 2), %rax
- addq %rdi, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
# endif
+ leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax
ret
.p2align 4
-L(first_vec_x3_check):
+L(last_vec_x3):
tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
+ subl $(CHAR_PER_VEC * 2), %esi
/* Check the end of data. */
- cmpq %rax, %rsi
- jbe L(max)
- addq $(VEC_SIZE * 3), %rax
- addq %rdi, %rax
- subq %rdx, %rax
+ cmpl %eax, %esi
+ jb L(max_end)
+ subq %rdx, %rdi
# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide bytes by 4 to get the wchar_t count. */
+ sarq $2, %rdi
# endif
+ leaq (CHAR_PER_VEC * 3)(%rdi, %rax), %rax
ret
-
- .p2align 4
-L(max):
+L(max_end):
movq %r8, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
-# endif
- ret
-
- .p2align 4
-L(zero):
- xorl %eax, %eax
ret
# endif
+ /* Cold case for crossing page with first load. */
.p2align 4
-L(first_vec_x0):
- tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- addq %rdi, %rax
- subq %rdx, %rax
+L(cross_page_boundary):
+ movq %rdi, %rdx
+ /* Align data to VEC_SIZE. */
+ andq $-VEC_SIZE, %rdi
+ VPCMP $0, (%rdi), %YMMZERO, %k0
+ kmovd %k0, %eax
+ /* Remove the leading bytes. */
# ifdef USE_AS_WCSLEN
- shrq $2, %rax
+ /* NB: Divide shift count by 4 since each bit in K0 represent 4
+ bytes. */
+ movl %edx, %ecx
+ shrl $2, %ecx
+ andl $(CHAR_PER_VEC - 1), %ecx
# endif
- ret
-
- .p2align 4
-L(first_vec_x1):
+ /* SHIFT_REG is ecx for USE_AS_WCSLEN and edx otherwise. */
+ sarxl %SHIFT_REG, %eax, %eax
+ testl %eax, %eax
+# ifndef USE_AS_STRNLEN
+ jz L(cross_page_continue)
tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- addq $VEC_SIZE, %rax
- addq %rdi, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
-# endif
ret
-
- .p2align 4
-L(first_vec_x2):
- tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- addq $(VEC_SIZE * 2), %rax
- addq %rdi, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
-# endif
+# else
+ jnz L(cross_page_less_vec)
+# ifndef USE_AS_WCSLEN
+ movl %edx, %ecx
+ andl $(CHAR_PER_VEC - 1), %ecx
+# endif
+ movl $CHAR_PER_VEC, %eax
+ subl %ecx, %eax
+ /* Check the end of data. */
+ cmpq %rax, %rsi
+ ja L(cross_page_continue)
+ movl %esi, %eax
ret
-
- .p2align 4
-L(4x_vec_end):
- VPCMP $0, %YMM1, %YMMZERO, %k0
- kmovd %k0, %eax
- testl %eax, %eax
- jnz L(first_vec_x0)
- VPCMP $0, %YMM2, %YMMZERO, %k1
- kmovd %k1, %eax
- testl %eax, %eax
- jnz L(first_vec_x1)
- VPCMP $0, %YMM3, %YMMZERO, %k2
- kmovd %k2, %eax
- testl %eax, %eax
- jnz L(first_vec_x2)
- VPCMP $0, %YMM4, %YMMZERO, %k3
- kmovd %k3, %eax
-L(first_vec_x3):
+L(cross_page_less_vec):
tzcntl %eax, %eax
-# ifdef USE_AS_WCSLEN
- /* NB: Multiply wchar_t count by 4 to get the number of bytes. */
- sall $2, %eax
-# endif
- addq $(VEC_SIZE * 3), %rax
- addq %rdi, %rax
- subq %rdx, %rax
-# ifdef USE_AS_WCSLEN
- shrq $2, %rax
-# endif
+ /* Select min of length and position of first null. */
+ cmpq %rax, %rsi
+ cmovb %esi, %eax
ret
+# endif
END (STRLEN)
#endif
--
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