1790 lines
43 KiB
Diff
1790 lines
43 KiB
Diff
commit 0d5b36c8cc15f064e302d29692853f8a760e1547
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Author: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Mon Jan 10 15:35:38 2022 -0600
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x86: Optimize strcmp-avx2.S
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Optimization are primarily to the loop logic and how the page cross
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logic interacts with the loop.
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The page cross logic is at times more expensive for short strings near
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the end of a page but not crossing the page. This is done to retest
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the page cross conditions with a non-faulty check and to improve the
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logic for entering the loop afterwards. This is only particular cases,
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however, and is general made up for by more than 10x improvements on
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the transition from the page cross -> loop case.
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The non-page cross cases are improved most for smaller sizes [0, 128]
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and go about even for (128, 4096]. The loop page cross logic is
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improved so some more significant speedup is seen there as well.
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test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass.
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Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
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(cherry picked from commit b77b06e0e296f1a2276c27a67e1d44f2cfa38d45)
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diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
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index fa70c994fc25dfd8..a0d1c65db11028bc 100644
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--- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
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+++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
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@@ -26,35 +26,57 @@
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# define PAGE_SIZE 4096
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-/* VEC_SIZE = Number of bytes in a ymm register */
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+ /* VEC_SIZE = Number of bytes in a ymm register. */
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# define VEC_SIZE 32
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-/* Shift for dividing by (VEC_SIZE * 4). */
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-# define DIVIDE_BY_VEC_4_SHIFT 7
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-# if (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT)
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-# error (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT)
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-# endif
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+# define VMOVU vmovdqu
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+# define VMOVA vmovdqa
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# ifdef USE_AS_WCSCMP
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-/* Compare packed dwords. */
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+ /* Compare packed dwords. */
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# define VPCMPEQ vpcmpeqd
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-/* Compare packed dwords and store minimum. */
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+ /* Compare packed dwords and store minimum. */
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# define VPMINU vpminud
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-/* 1 dword char == 4 bytes. */
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+ /* 1 dword char == 4 bytes. */
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# define SIZE_OF_CHAR 4
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# else
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-/* Compare packed bytes. */
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+ /* Compare packed bytes. */
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# define VPCMPEQ vpcmpeqb
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-/* Compare packed bytes and store minimum. */
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+ /* Compare packed bytes and store minimum. */
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# define VPMINU vpminub
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-/* 1 byte char == 1 byte. */
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+ /* 1 byte char == 1 byte. */
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# define SIZE_OF_CHAR 1
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# endif
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+# ifdef USE_AS_STRNCMP
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+# define LOOP_REG r9d
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+# define LOOP_REG64 r9
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+
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+# define OFFSET_REG8 r9b
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+# define OFFSET_REG r9d
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+# define OFFSET_REG64 r9
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+# else
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+# define LOOP_REG edx
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+# define LOOP_REG64 rdx
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+
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+# define OFFSET_REG8 dl
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+# define OFFSET_REG edx
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+# define OFFSET_REG64 rdx
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+# endif
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+
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# ifndef VZEROUPPER
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# define VZEROUPPER vzeroupper
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# endif
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+# if defined USE_AS_STRNCMP
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+# define VEC_OFFSET 0
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+# else
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+# define VEC_OFFSET (-VEC_SIZE)
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+# endif
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+
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+# define xmmZERO xmm15
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+# define ymmZERO ymm15
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+
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# ifndef SECTION
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# define SECTION(p) p##.avx
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# endif
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@@ -79,783 +101,1049 @@
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the maximum offset is reached before a difference is found, zero is
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returned. */
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- .section SECTION(.text),"ax",@progbits
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-ENTRY (STRCMP)
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+ .section SECTION(.text), "ax", @progbits
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+ENTRY(STRCMP)
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# ifdef USE_AS_STRNCMP
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- /* Check for simple cases (0 or 1) in offset. */
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+# ifdef __ILP32__
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+ /* Clear the upper 32 bits. */
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+ movl %edx, %rdx
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+# endif
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cmp $1, %RDX_LP
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- je L(char0)
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- jb L(zero)
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+ /* Signed comparison intentional. We use this branch to also
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+ test cases where length >= 2^63. These very large sizes can be
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+ handled with strcmp as there is no way for that length to
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+ actually bound the buffer. */
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+ jle L(one_or_less)
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# ifdef USE_AS_WCSCMP
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-# ifndef __ILP32__
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movq %rdx, %rcx
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- /* Check if length could overflow when multiplied by
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- sizeof(wchar_t). Checking top 8 bits will cover all potential
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- overflow cases as well as redirect cases where its impossible to
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- length to bound a valid memory region. In these cases just use
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- 'wcscmp'. */
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+
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+ /* Multiplying length by sizeof(wchar_t) can result in overflow.
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+ Check if that is possible. All cases where overflow are possible
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+ are cases where length is large enough that it can never be a
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+ bound on valid memory so just use wcscmp. */
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shrq $56, %rcx
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- jnz OVERFLOW_STRCMP
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-# endif
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- /* Convert units: from wide to byte char. */
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- shl $2, %RDX_LP
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+ jnz __wcscmp_avx2
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+
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+ leaq (, %rdx, 4), %rdx
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# endif
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- /* Register %r11 tracks the maximum offset. */
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- mov %RDX_LP, %R11_LP
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# endif
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+ vpxor %xmmZERO, %xmmZERO, %xmmZERO
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movl %edi, %eax
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- xorl %edx, %edx
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- /* Make %xmm7 (%ymm7) all zeros in this function. */
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- vpxor %xmm7, %xmm7, %xmm7
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orl %esi, %eax
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- andl $(PAGE_SIZE - 1), %eax
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- cmpl $(PAGE_SIZE - (VEC_SIZE * 4)), %eax
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- jg L(cross_page)
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- /* Start comparing 4 vectors. */
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- vmovdqu (%rdi), %ymm1
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- VPCMPEQ (%rsi), %ymm1, %ymm0
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- VPMINU %ymm1, %ymm0, %ymm0
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- VPCMPEQ %ymm7, %ymm0, %ymm0
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- vpmovmskb %ymm0, %ecx
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- testl %ecx, %ecx
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- je L(next_3_vectors)
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- tzcntl %ecx, %edx
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+ sall $20, %eax
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+ /* Check if s1 or s2 may cross a page in next 4x VEC loads. */
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+ cmpl $((PAGE_SIZE -(VEC_SIZE * 4)) << 20), %eax
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+ ja L(page_cross)
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+
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+L(no_page_cross):
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+ /* Safe to compare 4x vectors. */
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+ VMOVU (%rdi), %ymm0
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+ /* 1s where s1 and s2 equal. */
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+ VPCMPEQ (%rsi), %ymm0, %ymm1
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+ /* 1s at null CHAR. */
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+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
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+ /* 1s where s1 and s2 equal AND not null CHAR. */
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+ vpandn %ymm1, %ymm2, %ymm1
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+
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+ /* All 1s -> keep going, any 0s -> return. */
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+ vpmovmskb %ymm1, %ecx
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# ifdef USE_AS_STRNCMP
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- /* Return 0 if the mismatched index (%rdx) is after the maximum
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- offset (%r11). */
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- cmpq %r11, %rdx
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- jae L(zero)
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+ cmpq $VEC_SIZE, %rdx
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+ jbe L(vec_0_test_len)
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# endif
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+
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+ /* All 1s represents all equals. incl will overflow to zero in
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+ all equals case. Otherwise 1s will carry until position of first
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+ mismatch. */
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+ incl %ecx
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+ jz L(more_3x_vec)
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+
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+ .p2align 4,, 4
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+L(return_vec_0):
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+ tzcntl %ecx, %ecx
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# ifdef USE_AS_WCSCMP
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+ movl (%rdi, %rcx), %edx
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xorl %eax, %eax
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- movl (%rdi, %rdx), %ecx
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- cmpl (%rsi, %rdx), %ecx
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- je L(return)
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-L(wcscmp_return):
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+ cmpl (%rsi, %rcx), %edx
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+ je L(ret0)
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setl %al
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negl %eax
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orl $1, %eax
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-L(return):
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# else
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- movzbl (%rdi, %rdx), %eax
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- movzbl (%rsi, %rdx), %edx
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- subl %edx, %eax
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+ movzbl (%rdi, %rcx), %eax
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+ movzbl (%rsi, %rcx), %ecx
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+ subl %ecx, %eax
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# endif
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+L(ret0):
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L(return_vzeroupper):
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ZERO_UPPER_VEC_REGISTERS_RETURN
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- .p2align 4
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-L(return_vec_size):
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- tzcntl %ecx, %edx
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# ifdef USE_AS_STRNCMP
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- /* Return 0 if the mismatched index (%rdx + VEC_SIZE) is after
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- the maximum offset (%r11). */
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- addq $VEC_SIZE, %rdx
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- cmpq %r11, %rdx
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- jae L(zero)
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-# ifdef USE_AS_WCSCMP
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+ .p2align 4,, 8
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+L(vec_0_test_len):
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+ notl %ecx
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+ bzhil %edx, %ecx, %eax
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+ jnz L(return_vec_0)
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+ /* Align if will cross fetch block. */
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+ .p2align 4,, 2
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+L(ret_zero):
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xorl %eax, %eax
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- movl (%rdi, %rdx), %ecx
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- cmpl (%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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-# else
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- movzbl (%rdi, %rdx), %eax
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- movzbl (%rsi, %rdx), %edx
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- subl %edx, %eax
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-# endif
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-# else
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+ VZEROUPPER_RETURN
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+
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+ .p2align 4,, 5
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+L(one_or_less):
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+ jb L(ret_zero)
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# ifdef USE_AS_WCSCMP
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+ /* 'nbe' covers the case where length is negative (large
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+ unsigned). */
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+ jnbe __wcscmp_avx2
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+ movl (%rdi), %edx
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xorl %eax, %eax
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- movl VEC_SIZE(%rdi, %rdx), %ecx
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- cmpl VEC_SIZE(%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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+ cmpl (%rsi), %edx
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+ je L(ret1)
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+ setl %al
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+ negl %eax
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+ orl $1, %eax
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# else
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- movzbl VEC_SIZE(%rdi, %rdx), %eax
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- movzbl VEC_SIZE(%rsi, %rdx), %edx
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- subl %edx, %eax
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+ /* 'nbe' covers the case where length is negative (large
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+ unsigned). */
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+
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+ jnbe __strcmp_avx2
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+ movzbl (%rdi), %eax
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+ movzbl (%rsi), %ecx
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+ subl %ecx, %eax
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# endif
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+L(ret1):
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+ ret
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# endif
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- VZEROUPPER_RETURN
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- .p2align 4
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-L(return_2_vec_size):
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- tzcntl %ecx, %edx
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+ .p2align 4,, 10
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+L(return_vec_1):
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+ tzcntl %ecx, %ecx
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# ifdef USE_AS_STRNCMP
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- /* Return 0 if the mismatched index (%rdx + 2 * VEC_SIZE) is
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- after the maximum offset (%r11). */
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- addq $(VEC_SIZE * 2), %rdx
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- cmpq %r11, %rdx
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- jae L(zero)
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-# ifdef USE_AS_WCSCMP
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+ /* rdx must be > CHAR_PER_VEC so save to subtract w.o fear of
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+ overflow. */
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+ addq $-VEC_SIZE, %rdx
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+ cmpq %rcx, %rdx
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+ jbe L(ret_zero)
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+# endif
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+# ifdef USE_AS_WCSCMP
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+ movl VEC_SIZE(%rdi, %rcx), %edx
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xorl %eax, %eax
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- movl (%rdi, %rdx), %ecx
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- cmpl (%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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-# else
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- movzbl (%rdi, %rdx), %eax
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- movzbl (%rsi, %rdx), %edx
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- subl %edx, %eax
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-# endif
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+ cmpl VEC_SIZE(%rsi, %rcx), %edx
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+ je L(ret2)
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+ setl %al
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+ negl %eax
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+ orl $1, %eax
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# else
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-# ifdef USE_AS_WCSCMP
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- xorl %eax, %eax
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- movl (VEC_SIZE * 2)(%rdi, %rdx), %ecx
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- cmpl (VEC_SIZE * 2)(%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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-# else
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- movzbl (VEC_SIZE * 2)(%rdi, %rdx), %eax
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- movzbl (VEC_SIZE * 2)(%rsi, %rdx), %edx
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- subl %edx, %eax
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-# endif
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+ movzbl VEC_SIZE(%rdi, %rcx), %eax
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+ movzbl VEC_SIZE(%rsi, %rcx), %ecx
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+ subl %ecx, %eax
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# endif
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+L(ret2):
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VZEROUPPER_RETURN
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- .p2align 4
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-L(return_3_vec_size):
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- tzcntl %ecx, %edx
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+ .p2align 4,, 10
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# ifdef USE_AS_STRNCMP
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- /* Return 0 if the mismatched index (%rdx + 3 * VEC_SIZE) is
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- after the maximum offset (%r11). */
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- addq $(VEC_SIZE * 3), %rdx
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- cmpq %r11, %rdx
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- jae L(zero)
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-# ifdef USE_AS_WCSCMP
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+L(return_vec_3):
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+ salq $32, %rcx
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+# endif
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+
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+L(return_vec_2):
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+# ifndef USE_AS_STRNCMP
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+ tzcntl %ecx, %ecx
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+# else
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+ tzcntq %rcx, %rcx
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+ cmpq %rcx, %rdx
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+ jbe L(ret_zero)
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+# endif
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+
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+# ifdef USE_AS_WCSCMP
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+ movl (VEC_SIZE * 2)(%rdi, %rcx), %edx
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xorl %eax, %eax
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- movl (%rdi, %rdx), %ecx
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- cmpl (%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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-# else
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- movzbl (%rdi, %rdx), %eax
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- movzbl (%rsi, %rdx), %edx
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- subl %edx, %eax
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-# endif
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+ cmpl (VEC_SIZE * 2)(%rsi, %rcx), %edx
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+ je L(ret3)
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+ setl %al
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+ negl %eax
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+ orl $1, %eax
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# else
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+ movzbl (VEC_SIZE * 2)(%rdi, %rcx), %eax
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+ movzbl (VEC_SIZE * 2)(%rsi, %rcx), %ecx
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+ subl %ecx, %eax
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+# endif
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+L(ret3):
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+ VZEROUPPER_RETURN
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+
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+# ifndef USE_AS_STRNCMP
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+ .p2align 4,, 10
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+L(return_vec_3):
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+ tzcntl %ecx, %ecx
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# ifdef USE_AS_WCSCMP
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+ movl (VEC_SIZE * 3)(%rdi, %rcx), %edx
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xorl %eax, %eax
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- movl (VEC_SIZE * 3)(%rdi, %rdx), %ecx
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- cmpl (VEC_SIZE * 3)(%rsi, %rdx), %ecx
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- jne L(wcscmp_return)
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+ cmpl (VEC_SIZE * 3)(%rsi, %rcx), %edx
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+ je L(ret4)
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+ setl %al
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+ negl %eax
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+ orl $1, %eax
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# else
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- movzbl (VEC_SIZE * 3)(%rdi, %rdx), %eax
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- movzbl (VEC_SIZE * 3)(%rsi, %rdx), %edx
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- subl %edx, %eax
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+ movzbl (VEC_SIZE * 3)(%rdi, %rcx), %eax
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+ movzbl (VEC_SIZE * 3)(%rsi, %rcx), %ecx
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+ subl %ecx, %eax
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# endif
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-# endif
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+L(ret4):
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VZEROUPPER_RETURN
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+# endif
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+
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+ .p2align 4,, 10
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+L(more_3x_vec):
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+ /* Safe to compare 4x vectors. */
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+ VMOVU VEC_SIZE(%rdi), %ymm0
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+ VPCMPEQ VEC_SIZE(%rsi), %ymm0, %ymm1
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+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
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+ vpandn %ymm1, %ymm2, %ymm1
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+ vpmovmskb %ymm1, %ecx
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+ incl %ecx
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+ jnz L(return_vec_1)
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+
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+# ifdef USE_AS_STRNCMP
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+ subq $(VEC_SIZE * 2), %rdx
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+ jbe L(ret_zero)
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+# endif
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+
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+ VMOVU (VEC_SIZE * 2)(%rdi), %ymm0
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+ VPCMPEQ (VEC_SIZE * 2)(%rsi), %ymm0, %ymm1
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+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
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+ vpandn %ymm1, %ymm2, %ymm1
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+ vpmovmskb %ymm1, %ecx
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+ incl %ecx
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+ jnz L(return_vec_2)
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+
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+ VMOVU (VEC_SIZE * 3)(%rdi), %ymm0
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+ VPCMPEQ (VEC_SIZE * 3)(%rsi), %ymm0, %ymm1
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+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
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+ vpandn %ymm1, %ymm2, %ymm1
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+ vpmovmskb %ymm1, %ecx
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+ incl %ecx
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+ jnz L(return_vec_3)
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- .p2align 4
|
|
-L(next_3_vectors):
|
|
- vmovdqu VEC_SIZE(%rdi), %ymm6
|
|
- VPCMPEQ VEC_SIZE(%rsi), %ymm6, %ymm3
|
|
- VPMINU %ymm6, %ymm3, %ymm3
|
|
- VPCMPEQ %ymm7, %ymm3, %ymm3
|
|
- vpmovmskb %ymm3, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(return_vec_size)
|
|
- vmovdqu (VEC_SIZE * 2)(%rdi), %ymm5
|
|
- vmovdqu (VEC_SIZE * 3)(%rdi), %ymm4
|
|
- vmovdqu (VEC_SIZE * 3)(%rsi), %ymm0
|
|
- VPCMPEQ (VEC_SIZE * 2)(%rsi), %ymm5, %ymm2
|
|
- VPMINU %ymm5, %ymm2, %ymm2
|
|
- VPCMPEQ %ymm4, %ymm0, %ymm0
|
|
- VPCMPEQ %ymm7, %ymm2, %ymm2
|
|
- vpmovmskb %ymm2, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(return_2_vec_size)
|
|
- VPMINU %ymm4, %ymm0, %ymm0
|
|
- VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
- vpmovmskb %ymm0, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(return_3_vec_size)
|
|
-L(main_loop_header):
|
|
- leaq (VEC_SIZE * 4)(%rdi), %rdx
|
|
- movl $PAGE_SIZE, %ecx
|
|
- /* Align load via RAX. */
|
|
- andq $-(VEC_SIZE * 4), %rdx
|
|
- subq %rdi, %rdx
|
|
- leaq (%rdi, %rdx), %rax
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* Starting from this point, the maximum offset, or simply the
|
|
- 'offset', DECREASES by the same amount when base pointers are
|
|
- moved forward. Return 0 when:
|
|
- 1) On match: offset <= the matched vector index.
|
|
- 2) On mistmach, offset is before the mistmatched index.
|
|
+ cmpq $(VEC_SIZE * 2), %rdx
|
|
+ jbe L(ret_zero)
|
|
+# endif
|
|
+
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ /* any non-zero positive value that doesn't inference with 0x1.
|
|
*/
|
|
- subq %rdx, %r11
|
|
- jbe L(zero)
|
|
-# endif
|
|
- addq %rsi, %rdx
|
|
- movq %rdx, %rsi
|
|
- andl $(PAGE_SIZE - 1), %esi
|
|
- /* Number of bytes before page crossing. */
|
|
- subq %rsi, %rcx
|
|
- /* Number of VEC_SIZE * 4 blocks before page crossing. */
|
|
- shrq $DIVIDE_BY_VEC_4_SHIFT, %rcx
|
|
- /* ESI: Number of VEC_SIZE * 4 blocks before page crossing. */
|
|
- movl %ecx, %esi
|
|
- jmp L(loop_start)
|
|
+ movl $2, %r8d
|
|
|
|
+# else
|
|
+ xorl %r8d, %r8d
|
|
+# endif
|
|
+
|
|
+ /* The prepare labels are various entry points from the page
|
|
+ cross logic. */
|
|
+L(prepare_loop):
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ /* Store N + (VEC_SIZE * 4) and place check at the begining of
|
|
+ the loop. */
|
|
+ leaq (VEC_SIZE * 2)(%rdi, %rdx), %rdx
|
|
+# endif
|
|
+L(prepare_loop_no_len):
|
|
+
|
|
+ /* Align s1 and adjust s2 accordingly. */
|
|
+ subq %rdi, %rsi
|
|
+ andq $-(VEC_SIZE * 4), %rdi
|
|
+ addq %rdi, %rsi
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ subq %rdi, %rdx
|
|
+# endif
|
|
+
|
|
+L(prepare_loop_aligned):
|
|
+ /* eax stores distance from rsi to next page cross. These cases
|
|
+ need to be handled specially as the 4x loop could potentially
|
|
+ read memory past the length of s1 or s2 and across a page
|
|
+ boundary. */
|
|
+ movl $-(VEC_SIZE * 4), %eax
|
|
+ subl %esi, %eax
|
|
+ andl $(PAGE_SIZE - 1), %eax
|
|
+
|
|
+ /* Loop 4x comparisons at a time. */
|
|
.p2align 4
|
|
L(loop):
|
|
+
|
|
+ /* End condition for strncmp. */
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* Base pointers are moved forward by 4 * VEC_SIZE. Decrease
|
|
- the maximum offset (%r11) by the same amount. */
|
|
- subq $(VEC_SIZE * 4), %r11
|
|
- jbe L(zero)
|
|
-# endif
|
|
- addq $(VEC_SIZE * 4), %rax
|
|
- addq $(VEC_SIZE * 4), %rdx
|
|
-L(loop_start):
|
|
- testl %esi, %esi
|
|
- leal -1(%esi), %esi
|
|
- je L(loop_cross_page)
|
|
-L(back_to_loop):
|
|
- /* Main loop, comparing 4 vectors are a time. */
|
|
- vmovdqa (%rax), %ymm0
|
|
- vmovdqa VEC_SIZE(%rax), %ymm3
|
|
- VPCMPEQ (%rdx), %ymm0, %ymm4
|
|
- VPCMPEQ VEC_SIZE(%rdx), %ymm3, %ymm1
|
|
- VPMINU %ymm0, %ymm4, %ymm4
|
|
- VPMINU %ymm3, %ymm1, %ymm1
|
|
- vmovdqa (VEC_SIZE * 2)(%rax), %ymm2
|
|
- VPMINU %ymm1, %ymm4, %ymm0
|
|
- vmovdqa (VEC_SIZE * 3)(%rax), %ymm3
|
|
- VPCMPEQ (VEC_SIZE * 2)(%rdx), %ymm2, %ymm5
|
|
- VPCMPEQ (VEC_SIZE * 3)(%rdx), %ymm3, %ymm6
|
|
- VPMINU %ymm2, %ymm5, %ymm5
|
|
- VPMINU %ymm3, %ymm6, %ymm6
|
|
- VPMINU %ymm5, %ymm0, %ymm0
|
|
- VPMINU %ymm6, %ymm0, %ymm0
|
|
- VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
-
|
|
- /* Test each mask (32 bits) individually because for VEC_SIZE
|
|
- == 32 is not possible to OR the four masks and keep all bits
|
|
- in a 64-bit integer register, differing from SSE2 strcmp
|
|
- where ORing is possible. */
|
|
- vpmovmskb %ymm0, %ecx
|
|
+ subq $(VEC_SIZE * 4), %rdx
|
|
+ jbe L(ret_zero)
|
|
+# endif
|
|
+
|
|
+ subq $-(VEC_SIZE * 4), %rdi
|
|
+ subq $-(VEC_SIZE * 4), %rsi
|
|
+
|
|
+ /* Check if rsi loads will cross a page boundary. */
|
|
+ addl $-(VEC_SIZE * 4), %eax
|
|
+ jnb L(page_cross_during_loop)
|
|
+
|
|
+ /* Loop entry after handling page cross during loop. */
|
|
+L(loop_skip_page_cross_check):
|
|
+ VMOVA (VEC_SIZE * 0)(%rdi), %ymm0
|
|
+ VMOVA (VEC_SIZE * 1)(%rdi), %ymm2
|
|
+ VMOVA (VEC_SIZE * 2)(%rdi), %ymm4
|
|
+ VMOVA (VEC_SIZE * 3)(%rdi), %ymm6
|
|
+
|
|
+ /* ymm1 all 1s where s1 and s2 equal. All 0s otherwise. */
|
|
+ VPCMPEQ (VEC_SIZE * 0)(%rsi), %ymm0, %ymm1
|
|
+
|
|
+ VPCMPEQ (VEC_SIZE * 1)(%rsi), %ymm2, %ymm3
|
|
+ VPCMPEQ (VEC_SIZE * 2)(%rsi), %ymm4, %ymm5
|
|
+ VPCMPEQ (VEC_SIZE * 3)(%rsi), %ymm6, %ymm7
|
|
+
|
|
+
|
|
+ /* If any mismatches or null CHAR then 0 CHAR, otherwise non-
|
|
+ zero. */
|
|
+ vpand %ymm0, %ymm1, %ymm1
|
|
+
|
|
+
|
|
+ vpand %ymm2, %ymm3, %ymm3
|
|
+ vpand %ymm4, %ymm5, %ymm5
|
|
+ vpand %ymm6, %ymm7, %ymm7
|
|
+
|
|
+ VPMINU %ymm1, %ymm3, %ymm3
|
|
+ VPMINU %ymm5, %ymm7, %ymm7
|
|
+
|
|
+ /* Reduce all 0 CHARs for the 4x VEC into ymm7. */
|
|
+ VPMINU %ymm3, %ymm7, %ymm7
|
|
+
|
|
+ /* If any 0 CHAR then done. */
|
|
+ VPCMPEQ %ymm7, %ymmZERO, %ymm7
|
|
+ vpmovmskb %ymm7, %LOOP_REG
|
|
+ testl %LOOP_REG, %LOOP_REG
|
|
+ jz L(loop)
|
|
+
|
|
+ /* Find which VEC has the mismatch of end of string. */
|
|
+ VPCMPEQ %ymm1, %ymmZERO, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
testl %ecx, %ecx
|
|
- je L(loop)
|
|
- VPCMPEQ %ymm7, %ymm4, %ymm0
|
|
- vpmovmskb %ymm0, %edi
|
|
- testl %edi, %edi
|
|
- je L(test_vec)
|
|
- tzcntl %edi, %ecx
|
|
+ jnz L(return_vec_0_end)
|
|
+
|
|
+
|
|
+ VPCMPEQ %ymm3, %ymmZERO, %ymm3
|
|
+ vpmovmskb %ymm3, %ecx
|
|
+ testl %ecx, %ecx
|
|
+ jnz L(return_vec_1_end)
|
|
+
|
|
+L(return_vec_2_3_end):
|
|
# ifdef USE_AS_STRNCMP
|
|
- cmpq %rcx, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+ subq $(VEC_SIZE * 2), %rdx
|
|
+ jbe L(ret_zero_end)
|
|
+# endif
|
|
+
|
|
+ VPCMPEQ %ymm5, %ymmZERO, %ymm5
|
|
+ vpmovmskb %ymm5, %ecx
|
|
+ testl %ecx, %ecx
|
|
+ jnz L(return_vec_2_end)
|
|
+
|
|
+ /* LOOP_REG contains matches for null/mismatch from the loop. If
|
|
+ VEC 0,1,and 2 all have no null and no mismatches then mismatch
|
|
+ must entirely be from VEC 3 which is fully represented by
|
|
+ LOOP_REG. */
|
|
+ tzcntl %LOOP_REG, %LOOP_REG
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ subl $-(VEC_SIZE), %LOOP_REG
|
|
+ cmpq %LOOP_REG64, %rdx
|
|
+ jbe L(ret_zero_end)
|
|
+# endif
|
|
+
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ movl (VEC_SIZE * 2 - VEC_OFFSET)(%rdi, %LOOP_REG64), %ecx
|
|
xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %edi
|
|
- cmpl (%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ cmpl (VEC_SIZE * 2 - VEC_OFFSET)(%rsi, %LOOP_REG64), %ecx
|
|
+ je L(ret5)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
# else
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
- xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %edi
|
|
- cmpl (%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ movzbl (VEC_SIZE * 2 - VEC_OFFSET)(%rdi, %LOOP_REG64), %eax
|
|
+ movzbl (VEC_SIZE * 2 - VEC_OFFSET)(%rsi, %LOOP_REG64), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
+L(ret5):
|
|
VZEROUPPER_RETURN
|
|
|
|
- .p2align 4
|
|
-L(test_vec):
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* The first vector matched. Return 0 if the maximum offset
|
|
- (%r11) <= VEC_SIZE. */
|
|
- cmpq $VEC_SIZE, %r11
|
|
- jbe L(zero)
|
|
+ .p2align 4,, 2
|
|
+L(ret_zero_end):
|
|
+ xorl %eax, %eax
|
|
+ VZEROUPPER_RETURN
|
|
# endif
|
|
- VPCMPEQ %ymm7, %ymm1, %ymm1
|
|
- vpmovmskb %ymm1, %ecx
|
|
- testl %ecx, %ecx
|
|
- je L(test_2_vec)
|
|
- tzcntl %ecx, %edi
|
|
+
|
|
+
|
|
+ /* The L(return_vec_N_end) differ from L(return_vec_N) in that
|
|
+ they use the value of `r8` to negate the return value. This is
|
|
+ because the page cross logic can swap `rdi` and `rsi`. */
|
|
+ .p2align 4,, 10
|
|
# ifdef USE_AS_STRNCMP
|
|
- addq $VEC_SIZE, %rdi
|
|
- cmpq %rdi, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+L(return_vec_1_end):
|
|
+ salq $32, %rcx
|
|
+# endif
|
|
+L(return_vec_0_end):
|
|
+# ifndef USE_AS_STRNCMP
|
|
+ tzcntl %ecx, %ecx
|
|
+# else
|
|
+ tzcntq %rcx, %rcx
|
|
+ cmpq %rcx, %rdx
|
|
+ jbe L(ret_zero_end)
|
|
+# endif
|
|
+
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ movl (%rdi, %rcx), %edx
|
|
xorl %eax, %eax
|
|
- movl (%rsi, %rdi), %ecx
|
|
- cmpl (%rdx, %rdi), %ecx
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rdi), %eax
|
|
- movzbl (%rdx, %rdi), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ cmpl (%rsi, %rcx), %edx
|
|
+ je L(ret6)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
# else
|
|
+ movzbl (%rdi, %rcx), %eax
|
|
+ movzbl (%rsi, %rcx), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
+# endif
|
|
+L(ret6):
|
|
+ VZEROUPPER_RETURN
|
|
+
|
|
+# ifndef USE_AS_STRNCMP
|
|
+ .p2align 4,, 10
|
|
+L(return_vec_1_end):
|
|
+ tzcntl %ecx, %ecx
|
|
# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+ movl VEC_SIZE(%rdi, %rcx), %edx
|
|
xorl %eax, %eax
|
|
- movl VEC_SIZE(%rsi, %rdi), %ecx
|
|
- cmpl VEC_SIZE(%rdx, %rdi), %ecx
|
|
- jne L(wcscmp_return)
|
|
+ cmpl VEC_SIZE(%rsi, %rcx), %edx
|
|
+ je L(ret7)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
# else
|
|
- movzbl VEC_SIZE(%rax, %rdi), %eax
|
|
- movzbl VEC_SIZE(%rdx, %rdi), %edx
|
|
- subl %edx, %eax
|
|
+ movzbl VEC_SIZE(%rdi, %rcx), %eax
|
|
+ movzbl VEC_SIZE(%rsi, %rcx), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
-# endif
|
|
+L(ret7):
|
|
VZEROUPPER_RETURN
|
|
+# endif
|
|
|
|
- .p2align 4
|
|
-L(test_2_vec):
|
|
+ .p2align 4,, 10
|
|
+L(return_vec_2_end):
|
|
+ tzcntl %ecx, %ecx
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* The first 2 vectors matched. Return 0 if the maximum offset
|
|
- (%r11) <= 2 * VEC_SIZE. */
|
|
- cmpq $(VEC_SIZE * 2), %r11
|
|
- jbe L(zero)
|
|
+ cmpq %rcx, %rdx
|
|
+ jbe L(ret_zero_page_cross)
|
|
# endif
|
|
- VPCMPEQ %ymm7, %ymm5, %ymm5
|
|
- vpmovmskb %ymm5, %ecx
|
|
- testl %ecx, %ecx
|
|
- je L(test_3_vec)
|
|
- tzcntl %ecx, %edi
|
|
-# ifdef USE_AS_STRNCMP
|
|
- addq $(VEC_SIZE * 2), %rdi
|
|
- cmpq %rdi, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ movl (VEC_SIZE * 2)(%rdi, %rcx), %edx
|
|
xorl %eax, %eax
|
|
- movl (%rsi, %rdi), %ecx
|
|
- cmpl (%rdx, %rdi), %ecx
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rdi), %eax
|
|
- movzbl (%rdx, %rdi), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ cmpl (VEC_SIZE * 2)(%rsi, %rcx), %edx
|
|
+ je L(ret11)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
# else
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
- xorl %eax, %eax
|
|
- movl (VEC_SIZE * 2)(%rsi, %rdi), %ecx
|
|
- cmpl (VEC_SIZE * 2)(%rdx, %rdi), %ecx
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (VEC_SIZE * 2)(%rax, %rdi), %eax
|
|
- movzbl (VEC_SIZE * 2)(%rdx, %rdi), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ movzbl (VEC_SIZE * 2)(%rdi, %rcx), %eax
|
|
+ movzbl (VEC_SIZE * 2)(%rsi, %rcx), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
+L(ret11):
|
|
VZEROUPPER_RETURN
|
|
|
|
- .p2align 4
|
|
-L(test_3_vec):
|
|
+
|
|
+ /* Page cross in rsi in next 4x VEC. */
|
|
+
|
|
+ /* TODO: Improve logic here. */
|
|
+ .p2align 4,, 10
|
|
+L(page_cross_during_loop):
|
|
+ /* eax contains [distance_from_page - (VEC_SIZE * 4)]. */
|
|
+
|
|
+ /* Optimistically rsi and rdi and both aligned inwhich case we
|
|
+ don't need any logic here. */
|
|
+ cmpl $-(VEC_SIZE * 4), %eax
|
|
+ /* Don't adjust eax before jumping back to loop and we will
|
|
+ never hit page cross case again. */
|
|
+ je L(loop_skip_page_cross_check)
|
|
+
|
|
+ /* Check if we can safely load a VEC. */
|
|
+ cmpl $-(VEC_SIZE * 3), %eax
|
|
+ jle L(less_1x_vec_till_page_cross)
|
|
+
|
|
+ VMOVA (%rdi), %ymm0
|
|
+ VPCMPEQ (%rsi), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incl %ecx
|
|
+ jnz L(return_vec_0_end)
|
|
+
|
|
+ /* if distance >= 2x VEC then eax > -(VEC_SIZE * 2). */
|
|
+ cmpl $-(VEC_SIZE * 2), %eax
|
|
+ jg L(more_2x_vec_till_page_cross)
|
|
+
|
|
+ .p2align 4,, 4
|
|
+L(less_1x_vec_till_page_cross):
|
|
+ subl $-(VEC_SIZE * 4), %eax
|
|
+ /* Guranteed safe to read from rdi - VEC_SIZE here. The only
|
|
+ concerning case is first iteration if incoming s1 was near start
|
|
+ of a page and s2 near end. If s1 was near the start of the page
|
|
+ we already aligned up to nearest VEC_SIZE * 4 so gurnateed safe
|
|
+ to read back -VEC_SIZE. If rdi is truly at the start of a page
|
|
+ here, it means the previous page (rdi - VEC_SIZE) has already
|
|
+ been loaded earlier so must be valid. */
|
|
+ VMOVU -VEC_SIZE(%rdi, %rax), %ymm0
|
|
+ VPCMPEQ -VEC_SIZE(%rsi, %rax), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+
|
|
+ /* Mask of potentially valid bits. The lower bits can be out of
|
|
+ range comparisons (but safe regarding page crosses). */
|
|
+ movl $-1, %r10d
|
|
+ shlxl %esi, %r10d, %r10d
|
|
+ notl %ecx
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* The first 3 vectors matched. Return 0 if the maximum offset
|
|
- (%r11) <= 3 * VEC_SIZE. */
|
|
- cmpq $(VEC_SIZE * 3), %r11
|
|
- jbe L(zero)
|
|
-# endif
|
|
- VPCMPEQ %ymm7, %ymm6, %ymm6
|
|
- vpmovmskb %ymm6, %esi
|
|
- tzcntl %esi, %ecx
|
|
+ cmpq %rax, %rdx
|
|
+ jbe L(return_page_cross_end_check)
|
|
+# endif
|
|
+ movl %eax, %OFFSET_REG
|
|
+ addl $(PAGE_SIZE - VEC_SIZE * 4), %eax
|
|
+
|
|
+ andl %r10d, %ecx
|
|
+ jz L(loop_skip_page_cross_check)
|
|
+
|
|
+ .p2align 4,, 3
|
|
+L(return_page_cross_end):
|
|
+ tzcntl %ecx, %ecx
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- addq $(VEC_SIZE * 3), %rcx
|
|
- cmpq %rcx, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
- xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %esi
|
|
- cmpl (%rdx, %rcx), %esi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ leal -VEC_SIZE(%OFFSET_REG64, %rcx), %ecx
|
|
+L(return_page_cross_cmp_mem):
|
|
# else
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+ addl %OFFSET_REG, %ecx
|
|
+# endif
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ movl VEC_OFFSET(%rdi, %rcx), %edx
|
|
xorl %eax, %eax
|
|
- movl (VEC_SIZE * 3)(%rsi, %rcx), %esi
|
|
- cmpl (VEC_SIZE * 3)(%rdx, %rcx), %esi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (VEC_SIZE * 3)(%rax, %rcx), %eax
|
|
- movzbl (VEC_SIZE * 3)(%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ cmpl VEC_OFFSET(%rsi, %rcx), %edx
|
|
+ je L(ret8)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
+# else
|
|
+ movzbl VEC_OFFSET(%rdi, %rcx), %eax
|
|
+ movzbl VEC_OFFSET(%rsi, %rcx), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
+L(ret8):
|
|
VZEROUPPER_RETURN
|
|
|
|
- .p2align 4
|
|
-L(loop_cross_page):
|
|
- xorl %r10d, %r10d
|
|
- movq %rdx, %rcx
|
|
- /* Align load via RDX. We load the extra ECX bytes which should
|
|
- be ignored. */
|
|
- andl $((VEC_SIZE * 4) - 1), %ecx
|
|
- /* R10 is -RCX. */
|
|
- subq %rcx, %r10
|
|
-
|
|
- /* This works only if VEC_SIZE * 2 == 64. */
|
|
-# if (VEC_SIZE * 2) != 64
|
|
-# error (VEC_SIZE * 2) != 64
|
|
-# endif
|
|
-
|
|
- /* Check if the first VEC_SIZE * 2 bytes should be ignored. */
|
|
- cmpl $(VEC_SIZE * 2), %ecx
|
|
- jge L(loop_cross_page_2_vec)
|
|
-
|
|
- vmovdqu (%rax, %r10), %ymm2
|
|
- vmovdqu VEC_SIZE(%rax, %r10), %ymm3
|
|
- VPCMPEQ (%rdx, %r10), %ymm2, %ymm0
|
|
- VPCMPEQ VEC_SIZE(%rdx, %r10), %ymm3, %ymm1
|
|
- VPMINU %ymm2, %ymm0, %ymm0
|
|
- VPMINU %ymm3, %ymm1, %ymm1
|
|
- VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
- VPCMPEQ %ymm7, %ymm1, %ymm1
|
|
-
|
|
- vpmovmskb %ymm0, %edi
|
|
- vpmovmskb %ymm1, %esi
|
|
-
|
|
- salq $32, %rsi
|
|
- xorq %rsi, %rdi
|
|
-
|
|
- /* Since ECX < VEC_SIZE * 2, simply skip the first ECX bytes. */
|
|
- shrq %cl, %rdi
|
|
-
|
|
- testq %rdi, %rdi
|
|
- je L(loop_cross_page_2_vec)
|
|
- tzcntq %rdi, %rcx
|
|
# ifdef USE_AS_STRNCMP
|
|
- cmpq %rcx, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+ .p2align 4,, 10
|
|
+L(return_page_cross_end_check):
|
|
+ tzcntl %ecx, %ecx
|
|
+ leal -VEC_SIZE(%rax, %rcx), %ecx
|
|
+ cmpl %ecx, %edx
|
|
+ ja L(return_page_cross_cmp_mem)
|
|
xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %edi
|
|
- cmpl (%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
-# else
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
- xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %edi
|
|
- cmpl (%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
-# endif
|
|
VZEROUPPER_RETURN
|
|
+# endif
|
|
|
|
- .p2align 4
|
|
-L(loop_cross_page_2_vec):
|
|
- /* The first VEC_SIZE * 2 bytes match or are ignored. */
|
|
- vmovdqu (VEC_SIZE * 2)(%rax, %r10), %ymm2
|
|
- vmovdqu (VEC_SIZE * 3)(%rax, %r10), %ymm3
|
|
- VPCMPEQ (VEC_SIZE * 2)(%rdx, %r10), %ymm2, %ymm5
|
|
- VPMINU %ymm2, %ymm5, %ymm5
|
|
- VPCMPEQ (VEC_SIZE * 3)(%rdx, %r10), %ymm3, %ymm6
|
|
- VPCMPEQ %ymm7, %ymm5, %ymm5
|
|
- VPMINU %ymm3, %ymm6, %ymm6
|
|
- VPCMPEQ %ymm7, %ymm6, %ymm6
|
|
-
|
|
- vpmovmskb %ymm5, %edi
|
|
- vpmovmskb %ymm6, %esi
|
|
-
|
|
- salq $32, %rsi
|
|
- xorq %rsi, %rdi
|
|
|
|
- xorl %r8d, %r8d
|
|
- /* If ECX > VEC_SIZE * 2, skip ECX - (VEC_SIZE * 2) bytes. */
|
|
- subl $(VEC_SIZE * 2), %ecx
|
|
- jle 1f
|
|
- /* Skip ECX bytes. */
|
|
- shrq %cl, %rdi
|
|
- /* R8 has number of bytes skipped. */
|
|
- movl %ecx, %r8d
|
|
-1:
|
|
- /* Before jumping back to the loop, set ESI to the number of
|
|
- VEC_SIZE * 4 blocks before page crossing. */
|
|
- movl $(PAGE_SIZE / (VEC_SIZE * 4) - 1), %esi
|
|
-
|
|
- testq %rdi, %rdi
|
|
+ .p2align 4,, 10
|
|
+L(more_2x_vec_till_page_cross):
|
|
+ /* If more 2x vec till cross we will complete a full loop
|
|
+ iteration here. */
|
|
+
|
|
+ VMOVU VEC_SIZE(%rdi), %ymm0
|
|
+ VPCMPEQ VEC_SIZE(%rsi), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incl %ecx
|
|
+ jnz L(return_vec_1_end)
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* At this point, if %rdi value is 0, it already tested
|
|
- VEC_SIZE*4+%r10 byte starting from %rax. This label
|
|
- checks whether strncmp maximum offset reached or not. */
|
|
- je L(string_nbyte_offset_check)
|
|
-# else
|
|
- je L(back_to_loop)
|
|
+ cmpq $(VEC_SIZE * 2), %rdx
|
|
+ jbe L(ret_zero_in_loop_page_cross)
|
|
# endif
|
|
- tzcntq %rdi, %rcx
|
|
- addq %r10, %rcx
|
|
- /* Adjust for number of bytes skipped. */
|
|
- addq %r8, %rcx
|
|
+
|
|
+ subl $-(VEC_SIZE * 4), %eax
|
|
+
|
|
+ /* Safe to include comparisons from lower bytes. */
|
|
+ VMOVU -(VEC_SIZE * 2)(%rdi, %rax), %ymm0
|
|
+ VPCMPEQ -(VEC_SIZE * 2)(%rsi, %rax), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incl %ecx
|
|
+ jnz L(return_vec_page_cross_0)
|
|
+
|
|
+ VMOVU -(VEC_SIZE * 1)(%rdi, %rax), %ymm0
|
|
+ VPCMPEQ -(VEC_SIZE * 1)(%rsi, %rax), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incl %ecx
|
|
+ jnz L(return_vec_page_cross_1)
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- addq $(VEC_SIZE * 2), %rcx
|
|
- subq %rcx, %r11
|
|
- jbe L(zero)
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
+ /* Must check length here as length might proclude reading next
|
|
+ page. */
|
|
+ cmpq %rax, %rdx
|
|
+ jbe L(ret_zero_in_loop_page_cross)
|
|
+# endif
|
|
+
|
|
+ /* Finish the loop. */
|
|
+ VMOVA (VEC_SIZE * 2)(%rdi), %ymm4
|
|
+ VMOVA (VEC_SIZE * 3)(%rdi), %ymm6
|
|
+
|
|
+ VPCMPEQ (VEC_SIZE * 2)(%rsi), %ymm4, %ymm5
|
|
+ VPCMPEQ (VEC_SIZE * 3)(%rsi), %ymm6, %ymm7
|
|
+ vpand %ymm4, %ymm5, %ymm5
|
|
+ vpand %ymm6, %ymm7, %ymm7
|
|
+ VPMINU %ymm5, %ymm7, %ymm7
|
|
+ VPCMPEQ %ymm7, %ymmZERO, %ymm7
|
|
+ vpmovmskb %ymm7, %LOOP_REG
|
|
+ testl %LOOP_REG, %LOOP_REG
|
|
+ jnz L(return_vec_2_3_end)
|
|
+
|
|
+ /* Best for code size to include ucond-jmp here. Would be faster
|
|
+ if this case is hot to duplicate the L(return_vec_2_3_end) code
|
|
+ as fall-through and have jump back to loop on mismatch
|
|
+ comparison. */
|
|
+ subq $-(VEC_SIZE * 4), %rdi
|
|
+ subq $-(VEC_SIZE * 4), %rsi
|
|
+ addl $(PAGE_SIZE - VEC_SIZE * 8), %eax
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ subq $(VEC_SIZE * 4), %rdx
|
|
+ ja L(loop_skip_page_cross_check)
|
|
+L(ret_zero_in_loop_page_cross):
|
|
xorl %eax, %eax
|
|
- movl (%rsi, %rcx), %edi
|
|
- cmpl (%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rax, %rcx), %eax
|
|
- movzbl (%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ VZEROUPPER_RETURN
|
|
# else
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movq %rax, %rsi
|
|
- xorl %eax, %eax
|
|
- movl (VEC_SIZE * 2)(%rsi, %rcx), %edi
|
|
- cmpl (VEC_SIZE * 2)(%rdx, %rcx), %edi
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (VEC_SIZE * 2)(%rax, %rcx), %eax
|
|
- movzbl (VEC_SIZE * 2)(%rdx, %rcx), %edx
|
|
- subl %edx, %eax
|
|
-# endif
|
|
+ jmp L(loop_skip_page_cross_check)
|
|
# endif
|
|
- VZEROUPPER_RETURN
|
|
|
|
+
|
|
+ .p2align 4,, 10
|
|
+L(return_vec_page_cross_0):
|
|
+ addl $-VEC_SIZE, %eax
|
|
+L(return_vec_page_cross_1):
|
|
+ tzcntl %ecx, %ecx
|
|
# ifdef USE_AS_STRNCMP
|
|
-L(string_nbyte_offset_check):
|
|
- leaq (VEC_SIZE * 4)(%r10), %r10
|
|
- cmpq %r10, %r11
|
|
- jbe L(zero)
|
|
- jmp L(back_to_loop)
|
|
+ leal -VEC_SIZE(%rax, %rcx), %ecx
|
|
+ cmpq %rcx, %rdx
|
|
+ jbe L(ret_zero_in_loop_page_cross)
|
|
+# else
|
|
+ addl %eax, %ecx
|
|
# endif
|
|
|
|
- .p2align 4
|
|
-L(cross_page_loop):
|
|
- /* Check one byte/dword at a time. */
|
|
# ifdef USE_AS_WCSCMP
|
|
- cmpl %ecx, %eax
|
|
+ movl VEC_OFFSET(%rdi, %rcx), %edx
|
|
+ xorl %eax, %eax
|
|
+ cmpl VEC_OFFSET(%rsi, %rcx), %edx
|
|
+ je L(ret9)
|
|
+ setl %al
|
|
+ negl %eax
|
|
+ xorl %r8d, %eax
|
|
# else
|
|
+ movzbl VEC_OFFSET(%rdi, %rcx), %eax
|
|
+ movzbl VEC_OFFSET(%rsi, %rcx), %ecx
|
|
subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
- jne L(different)
|
|
- addl $SIZE_OF_CHAR, %edx
|
|
- cmpl $(VEC_SIZE * 4), %edx
|
|
- je L(main_loop_header)
|
|
-# ifdef USE_AS_STRNCMP
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
+L(ret9):
|
|
+ VZEROUPPER_RETURN
|
|
+
|
|
+
|
|
+ .p2align 4,, 10
|
|
+L(page_cross):
|
|
+# ifndef USE_AS_STRNCMP
|
|
+ /* If both are VEC aligned we don't need any special logic here.
|
|
+ Only valid for strcmp where stop condition is guranteed to be
|
|
+ reachable by just reading memory. */
|
|
+ testl $((VEC_SIZE - 1) << 20), %eax
|
|
+ jz L(no_page_cross)
|
|
# endif
|
|
+
|
|
+ movl %edi, %eax
|
|
+ movl %esi, %ecx
|
|
+ andl $(PAGE_SIZE - 1), %eax
|
|
+ andl $(PAGE_SIZE - 1), %ecx
|
|
+
|
|
+ xorl %OFFSET_REG, %OFFSET_REG
|
|
+
|
|
+ /* Check which is closer to page cross, s1 or s2. */
|
|
+ cmpl %eax, %ecx
|
|
+ jg L(page_cross_s2)
|
|
+
|
|
+ /* The previous page cross check has false positives. Check for
|
|
+ true positive as page cross logic is very expensive. */
|
|
+ subl $(PAGE_SIZE - VEC_SIZE * 4), %eax
|
|
+ jbe L(no_page_cross)
|
|
+
|
|
+ /* Set r8 to not interfere with normal return value (rdi and rsi
|
|
+ did not swap). */
|
|
# ifdef USE_AS_WCSCMP
|
|
- movl (%rdi, %rdx), %eax
|
|
- movl (%rsi, %rdx), %ecx
|
|
+ /* any non-zero positive value that doesn't inference with 0x1.
|
|
+ */
|
|
+ movl $2, %r8d
|
|
# else
|
|
- movzbl (%rdi, %rdx), %eax
|
|
- movzbl (%rsi, %rdx), %ecx
|
|
+ xorl %r8d, %r8d
|
|
# endif
|
|
- /* Check null char. */
|
|
- testl %eax, %eax
|
|
- jne L(cross_page_loop)
|
|
- /* Since %eax == 0, subtract is OK for both SIGNED and UNSIGNED
|
|
- comparisons. */
|
|
- subl %ecx, %eax
|
|
-# ifndef USE_AS_WCSCMP
|
|
-L(different):
|
|
+
|
|
+ /* Check if less than 1x VEC till page cross. */
|
|
+ subl $(VEC_SIZE * 3), %eax
|
|
+ jg L(less_1x_vec_till_page)
|
|
+
|
|
+ /* If more than 1x VEC till page cross, loop throuh safely
|
|
+ loadable memory until within 1x VEC of page cross. */
|
|
+
|
|
+ .p2align 4,, 10
|
|
+L(page_cross_loop):
|
|
+
|
|
+ VMOVU (%rdi, %OFFSET_REG64), %ymm0
|
|
+ VPCMPEQ (%rsi, %OFFSET_REG64), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incl %ecx
|
|
+
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
+ addl $VEC_SIZE, %OFFSET_REG
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ cmpq %OFFSET_REG64, %rdx
|
|
+ jbe L(ret_zero_page_cross)
|
|
# endif
|
|
- VZEROUPPER_RETURN
|
|
+ addl $VEC_SIZE, %eax
|
|
+ jl L(page_cross_loop)
|
|
+
|
|
+ subl %eax, %OFFSET_REG
|
|
+ /* OFFSET_REG has distance to page cross - VEC_SIZE. Guranteed
|
|
+ to not cross page so is safe to load. Since we have already
|
|
+ loaded at least 1 VEC from rsi it is also guranteed to be safe.
|
|
+ */
|
|
+
|
|
+ VMOVU (%rdi, %OFFSET_REG64), %ymm0
|
|
+ VPCMPEQ (%rsi, %OFFSET_REG64), %ymm0, %ymm1
|
|
+ VPCMPEQ %ymm0, %ymmZERO, %ymm2
|
|
+ vpandn %ymm1, %ymm2, %ymm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ leal VEC_SIZE(%OFFSET_REG64), %eax
|
|
+ cmpq %rax, %rdx
|
|
+ jbe L(check_ret_vec_page_cross2)
|
|
+ addq %rdi, %rdx
|
|
+# endif
|
|
+ incl %ecx
|
|
+ jz L(prepare_loop_no_len)
|
|
|
|
+ .p2align 4,, 4
|
|
+L(ret_vec_page_cross):
|
|
+# ifndef USE_AS_STRNCMP
|
|
+L(check_ret_vec_page_cross):
|
|
+# endif
|
|
+ tzcntl %ecx, %ecx
|
|
+ addl %OFFSET_REG, %ecx
|
|
+L(ret_vec_page_cross_cont):
|
|
# ifdef USE_AS_WCSCMP
|
|
- .p2align 4
|
|
-L(different):
|
|
- /* Use movl to avoid modifying EFLAGS. */
|
|
- movl $0, %eax
|
|
+ movl (%rdi, %rcx), %edx
|
|
+ xorl %eax, %eax
|
|
+ cmpl (%rsi, %rcx), %edx
|
|
+ je L(ret12)
|
|
setl %al
|
|
negl %eax
|
|
- orl $1, %eax
|
|
- VZEROUPPER_RETURN
|
|
+ xorl %r8d, %eax
|
|
+# else
|
|
+ movzbl (%rdi, %rcx), %eax
|
|
+ movzbl (%rsi, %rcx), %ecx
|
|
+ subl %ecx, %eax
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
# endif
|
|
+L(ret12):
|
|
+ VZEROUPPER_RETURN
|
|
|
|
# ifdef USE_AS_STRNCMP
|
|
- .p2align 4
|
|
-L(zero):
|
|
+ .p2align 4,, 10
|
|
+L(check_ret_vec_page_cross2):
|
|
+ incl %ecx
|
|
+L(check_ret_vec_page_cross):
|
|
+ tzcntl %ecx, %ecx
|
|
+ addl %OFFSET_REG, %ecx
|
|
+ cmpq %rcx, %rdx
|
|
+ ja L(ret_vec_page_cross_cont)
|
|
+ .p2align 4,, 2
|
|
+L(ret_zero_page_cross):
|
|
xorl %eax, %eax
|
|
VZEROUPPER_RETURN
|
|
+# endif
|
|
|
|
- .p2align 4
|
|
-L(char0):
|
|
-# ifdef USE_AS_WCSCMP
|
|
- xorl %eax, %eax
|
|
- movl (%rdi), %ecx
|
|
- cmpl (%rsi), %ecx
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rsi), %ecx
|
|
- movzbl (%rdi), %eax
|
|
- subl %ecx, %eax
|
|
-# endif
|
|
- VZEROUPPER_RETURN
|
|
+ .p2align 4,, 4
|
|
+L(page_cross_s2):
|
|
+ /* Ensure this is a true page cross. */
|
|
+ subl $(PAGE_SIZE - VEC_SIZE * 4), %ecx
|
|
+ jbe L(no_page_cross)
|
|
+
|
|
+
|
|
+ movl %ecx, %eax
|
|
+ movq %rdi, %rcx
|
|
+ movq %rsi, %rdi
|
|
+ movq %rcx, %rsi
|
|
+
|
|
+ /* set r8 to negate return value as rdi and rsi swapped. */
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ movl $-4, %r8d
|
|
+# else
|
|
+ movl $-1, %r8d
|
|
# endif
|
|
+ xorl %OFFSET_REG, %OFFSET_REG
|
|
|
|
- .p2align 4
|
|
-L(last_vector):
|
|
- addq %rdx, %rdi
|
|
- addq %rdx, %rsi
|
|
+ /* Check if more than 1x VEC till page cross. */
|
|
+ subl $(VEC_SIZE * 3), %eax
|
|
+ jle L(page_cross_loop)
|
|
+
|
|
+ .p2align 4,, 6
|
|
+L(less_1x_vec_till_page):
|
|
+ /* Find largest load size we can use. */
|
|
+ cmpl $16, %eax
|
|
+ ja L(less_16_till_page)
|
|
+
|
|
+ VMOVU (%rdi), %xmm0
|
|
+ VPCMPEQ (%rsi), %xmm0, %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incw %cx
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
+ movl $16, %OFFSET_REG
|
|
# ifdef USE_AS_STRNCMP
|
|
- subq %rdx, %r11
|
|
+ cmpq %OFFSET_REG64, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case0)
|
|
+ subl %eax, %OFFSET_REG
|
|
+# else
|
|
+ /* Explicit check for 16 byte alignment. */
|
|
+ subl %eax, %OFFSET_REG
|
|
+ jz L(prepare_loop)
|
|
# endif
|
|
- tzcntl %ecx, %edx
|
|
+
|
|
+ VMOVU (%rdi, %OFFSET_REG64), %xmm0
|
|
+ VPCMPEQ (%rsi, %OFFSET_REG64), %xmm0, %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incw %cx
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
+ addl $16, %OFFSET_REG
|
|
+ subq %OFFSET_REG64, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case0)
|
|
+ subq $-(VEC_SIZE * 4), %rdx
|
|
+
|
|
+ leaq -(VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq -(VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
+# else
|
|
+ leaq (16 - VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq (16 - VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
# endif
|
|
-# ifdef USE_AS_WCSCMP
|
|
+ jmp L(prepare_loop_aligned)
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ .p2align 4,, 2
|
|
+L(ret_zero_page_cross_slow_case0):
|
|
xorl %eax, %eax
|
|
- movl (%rdi, %rdx), %ecx
|
|
- cmpl (%rsi, %rdx), %ecx
|
|
- jne L(wcscmp_return)
|
|
-# else
|
|
- movzbl (%rdi, %rdx), %eax
|
|
- movzbl (%rsi, %rdx), %edx
|
|
- subl %edx, %eax
|
|
+ ret
|
|
# endif
|
|
- VZEROUPPER_RETURN
|
|
|
|
- /* Comparing on page boundary region requires special treatment:
|
|
- It must done one vector at the time, starting with the wider
|
|
- ymm vector if possible, if not, with xmm. If fetching 16 bytes
|
|
- (xmm) still passes the boundary, byte comparison must be done.
|
|
- */
|
|
- .p2align 4
|
|
-L(cross_page):
|
|
- /* Try one ymm vector at a time. */
|
|
- cmpl $(PAGE_SIZE - VEC_SIZE), %eax
|
|
- jg L(cross_page_1_vector)
|
|
-L(loop_1_vector):
|
|
- vmovdqu (%rdi, %rdx), %ymm1
|
|
- VPCMPEQ (%rsi, %rdx), %ymm1, %ymm0
|
|
- VPMINU %ymm1, %ymm0, %ymm0
|
|
- VPCMPEQ %ymm7, %ymm0, %ymm0
|
|
- vpmovmskb %ymm0, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(last_vector)
|
|
|
|
- addl $VEC_SIZE, %edx
|
|
+ .p2align 4,, 10
|
|
+L(less_16_till_page):
|
|
+ /* Find largest load size we can use. */
|
|
+ cmpl $24, %eax
|
|
+ ja L(less_8_till_page)
|
|
|
|
- addl $VEC_SIZE, %eax
|
|
-# ifdef USE_AS_STRNCMP
|
|
- /* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
- (%r11). */
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
-# endif
|
|
- cmpl $(PAGE_SIZE - VEC_SIZE), %eax
|
|
- jle L(loop_1_vector)
|
|
-L(cross_page_1_vector):
|
|
- /* Less than 32 bytes to check, try one xmm vector. */
|
|
- cmpl $(PAGE_SIZE - 16), %eax
|
|
- jg L(cross_page_1_xmm)
|
|
- vmovdqu (%rdi, %rdx), %xmm1
|
|
- VPCMPEQ (%rsi, %rdx), %xmm1, %xmm0
|
|
- VPMINU %xmm1, %xmm0, %xmm0
|
|
- VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
- vpmovmskb %xmm0, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(last_vector)
|
|
+ vmovq (%rdi), %xmm0
|
|
+ vmovq (%rsi), %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ VPCMPEQ %xmm1, %xmm0, %xmm1
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incb %cl
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
|
|
- addl $16, %edx
|
|
-# ifndef USE_AS_WCSCMP
|
|
- addl $16, %eax
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ cmpq $8, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case0)
|
|
# endif
|
|
+ movl $24, %OFFSET_REG
|
|
+ /* Explicit check for 16 byte alignment. */
|
|
+ subl %eax, %OFFSET_REG
|
|
+
|
|
+
|
|
+
|
|
+ vmovq (%rdi, %OFFSET_REG64), %xmm0
|
|
+ vmovq (%rsi, %OFFSET_REG64), %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ VPCMPEQ %xmm1, %xmm0, %xmm1
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ incb %cl
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
+
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
- (%r11). */
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
-# endif
|
|
-
|
|
-L(cross_page_1_xmm):
|
|
-# ifndef USE_AS_WCSCMP
|
|
- /* Less than 16 bytes to check, try 8 byte vector. NB: No need
|
|
- for wcscmp nor wcsncmp since wide char is 4 bytes. */
|
|
- cmpl $(PAGE_SIZE - 8), %eax
|
|
- jg L(cross_page_8bytes)
|
|
- vmovq (%rdi, %rdx), %xmm1
|
|
- vmovq (%rsi, %rdx), %xmm0
|
|
- VPCMPEQ %xmm0, %xmm1, %xmm0
|
|
- VPMINU %xmm1, %xmm0, %xmm0
|
|
- VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
- vpmovmskb %xmm0, %ecx
|
|
- /* Only last 8 bits are valid. */
|
|
- andl $0xff, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(last_vector)
|
|
+ addl $8, %OFFSET_REG
|
|
+ subq %OFFSET_REG64, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case0)
|
|
+ subq $-(VEC_SIZE * 4), %rdx
|
|
|
|
- addl $8, %edx
|
|
- addl $8, %eax
|
|
+ leaq -(VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq -(VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
+# else
|
|
+ leaq (8 - VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq (8 - VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
+# endif
|
|
+ jmp L(prepare_loop_aligned)
|
|
+
|
|
+
|
|
+ .p2align 4,, 10
|
|
+L(less_8_till_page):
|
|
+# ifdef USE_AS_WCSCMP
|
|
+ /* If using wchar then this is the only check before we reach
|
|
+ the page boundary. */
|
|
+ movl (%rdi), %eax
|
|
+ movl (%rsi), %ecx
|
|
+ cmpl %ecx, %eax
|
|
+ jnz L(ret_less_8_wcs)
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
- (%r11). */
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
+ addq %rdi, %rdx
|
|
+ /* We already checked for len <= 1 so cannot hit that case here.
|
|
+ */
|
|
# endif
|
|
+ testl %eax, %eax
|
|
+ jnz L(prepare_loop_no_len)
|
|
+ ret
|
|
|
|
-L(cross_page_8bytes):
|
|
- /* Less than 8 bytes to check, try 4 byte vector. */
|
|
- cmpl $(PAGE_SIZE - 4), %eax
|
|
- jg L(cross_page_4bytes)
|
|
- vmovd (%rdi, %rdx), %xmm1
|
|
- vmovd (%rsi, %rdx), %xmm0
|
|
- VPCMPEQ %xmm0, %xmm1, %xmm0
|
|
- VPMINU %xmm1, %xmm0, %xmm0
|
|
- VPCMPEQ %xmm7, %xmm0, %xmm0
|
|
- vpmovmskb %xmm0, %ecx
|
|
- /* Only last 4 bits are valid. */
|
|
- andl $0xf, %ecx
|
|
- testl %ecx, %ecx
|
|
- jne L(last_vector)
|
|
+ .p2align 4,, 8
|
|
+L(ret_less_8_wcs):
|
|
+ setl %OFFSET_REG8
|
|
+ negl %OFFSET_REG
|
|
+ movl %OFFSET_REG, %eax
|
|
+ xorl %r8d, %eax
|
|
+ ret
|
|
+
|
|
+# else
|
|
+
|
|
+ /* Find largest load size we can use. */
|
|
+ cmpl $28, %eax
|
|
+ ja L(less_4_till_page)
|
|
+
|
|
+ vmovd (%rdi), %xmm0
|
|
+ vmovd (%rsi), %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ VPCMPEQ %xmm1, %xmm0, %xmm1
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ subl $0xf, %ecx
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
|
|
- addl $4, %edx
|
|
# ifdef USE_AS_STRNCMP
|
|
- /* Return 0 if the current offset (%rdx) >= the maximum offset
|
|
- (%r11). */
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
+ cmpq $4, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case1)
|
|
# endif
|
|
+ movl $28, %OFFSET_REG
|
|
+ /* Explicit check for 16 byte alignment. */
|
|
+ subl %eax, %OFFSET_REG
|
|
|
|
-L(cross_page_4bytes):
|
|
-# endif
|
|
- /* Less than 4 bytes to check, try one byte/dword at a time. */
|
|
-# ifdef USE_AS_STRNCMP
|
|
- cmpq %r11, %rdx
|
|
- jae L(zero)
|
|
-# endif
|
|
-# ifdef USE_AS_WCSCMP
|
|
- movl (%rdi, %rdx), %eax
|
|
- movl (%rsi, %rdx), %ecx
|
|
-# else
|
|
- movzbl (%rdi, %rdx), %eax
|
|
- movzbl (%rsi, %rdx), %ecx
|
|
-# endif
|
|
- testl %eax, %eax
|
|
- jne L(cross_page_loop)
|
|
+
|
|
+
|
|
+ vmovd (%rdi, %OFFSET_REG64), %xmm0
|
|
+ vmovd (%rsi, %OFFSET_REG64), %xmm1
|
|
+ VPCMPEQ %xmm0, %xmmZERO, %xmm2
|
|
+ VPCMPEQ %xmm1, %xmm0, %xmm1
|
|
+ vpandn %xmm1, %xmm2, %xmm1
|
|
+ vpmovmskb %ymm1, %ecx
|
|
+ subl $0xf, %ecx
|
|
+ jnz L(check_ret_vec_page_cross)
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ addl $4, %OFFSET_REG
|
|
+ subq %OFFSET_REG64, %rdx
|
|
+ jbe L(ret_zero_page_cross_slow_case1)
|
|
+ subq $-(VEC_SIZE * 4), %rdx
|
|
+
|
|
+ leaq -(VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq -(VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
+# else
|
|
+ leaq (4 - VEC_SIZE * 4)(%rdi, %OFFSET_REG64), %rdi
|
|
+ leaq (4 - VEC_SIZE * 4)(%rsi, %OFFSET_REG64), %rsi
|
|
+# endif
|
|
+ jmp L(prepare_loop_aligned)
|
|
+
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ .p2align 4,, 2
|
|
+L(ret_zero_page_cross_slow_case1):
|
|
+ xorl %eax, %eax
|
|
+ ret
|
|
+# endif
|
|
+
|
|
+ .p2align 4,, 10
|
|
+L(less_4_till_page):
|
|
+ subq %rdi, %rsi
|
|
+ /* Extremely slow byte comparison loop. */
|
|
+L(less_4_loop):
|
|
+ movzbl (%rdi), %eax
|
|
+ movzbl (%rsi, %rdi), %ecx
|
|
subl %ecx, %eax
|
|
- VZEROUPPER_RETURN
|
|
-END (STRCMP)
|
|
+ jnz L(ret_less_4_loop)
|
|
+ testl %ecx, %ecx
|
|
+ jz L(ret_zero_4_loop)
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ decq %rdx
|
|
+ jz L(ret_zero_4_loop)
|
|
+# endif
|
|
+ incq %rdi
|
|
+ /* end condition is reach page boundary (rdi is aligned). */
|
|
+ testl $31, %edi
|
|
+ jnz L(less_4_loop)
|
|
+ leaq -(VEC_SIZE * 4)(%rdi, %rsi), %rsi
|
|
+ addq $-(VEC_SIZE * 4), %rdi
|
|
+# ifdef USE_AS_STRNCMP
|
|
+ subq $-(VEC_SIZE * 4), %rdx
|
|
+# endif
|
|
+ jmp L(prepare_loop_aligned)
|
|
+
|
|
+L(ret_zero_4_loop):
|
|
+ xorl %eax, %eax
|
|
+ ret
|
|
+L(ret_less_4_loop):
|
|
+ xorl %r8d, %eax
|
|
+ subl %r8d, %eax
|
|
+ ret
|
|
+# endif
|
|
+END(STRCMP)
|
|
#endif
|