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852 lines
21 KiB
852 lines
21 KiB
From 4ad473e97acdc5f6d811755b67c09f2128a644ce Mon Sep 17 00:00:00 2001
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From: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Mon, 17 May 2021 13:57:24 -0400
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Subject: [PATCH] x86: Optimize memcmp-evex-movbe.S
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Content-type: text/plain; charset=UTF-8
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No bug. This commit optimizes memcmp-evex.S. The optimizations include
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adding a new vec compare path for small sizes, reorganizing the entry
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control flow, removing some unnecissary ALU instructions from the main
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loop, and most importantly replacing the heavy use of vpcmp + kand
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logic with vpxor + vptern. test-memcmp and test-wmemcmp are both
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passing.
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Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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---
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sysdeps/x86_64/multiarch/memcmp-evex-movbe.S | 710 +++++++++++--------
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1 file changed, 408 insertions(+), 302 deletions(-)
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diff --git a/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S b/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S
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index 9c093972..654dc7ac 100644
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--- a/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S
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+++ b/sysdeps/x86_64/multiarch/memcmp-evex-movbe.S
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@@ -19,17 +19,22 @@
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#if IS_IN (libc)
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/* memcmp/wmemcmp is implemented as:
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- 1. For size from 2 to 7 bytes, load as big endian with movbe and bswap
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- to avoid branches.
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- 2. Use overlapping compare to avoid branch.
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- 3. Use vector compare when size >= 4 bytes for memcmp or size >= 8
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- bytes for wmemcmp.
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- 4. If size is 8 * VEC_SIZE or less, unroll the loop.
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- 5. Compare 4 * VEC_SIZE at a time with the aligned first memory
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+ 1. Use ymm vector compares when possible. The only case where
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+ vector compares is not possible for when size < CHAR_PER_VEC
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+ and loading from either s1 or s2 would cause a page cross.
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+ 2. For size from 2 to 7 bytes on page cross, load as big endian
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+ with movbe and bswap to avoid branches.
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+ 3. Use xmm vector compare when size >= 4 bytes for memcmp or
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+ size >= 8 bytes for wmemcmp.
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+ 4. Optimistically compare up to first 4 * CHAR_PER_VEC one at a
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+ to check for early mismatches. Only do this if its guranteed the
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+ work is not wasted.
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+ 5. If size is 8 * VEC_SIZE or less, unroll the loop.
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+ 6. Compare 4 * VEC_SIZE at a time with the aligned first memory
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area.
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- 6. Use 2 vector compares when size is 2 * VEC_SIZE or less.
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- 7. Use 4 vector compares when size is 4 * VEC_SIZE or less.
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- 8. Use 8 vector compares when size is 8 * VEC_SIZE or less. */
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+ 7. Use 2 vector compares when size is 2 * CHAR_PER_VEC or less.
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+ 8. Use 4 vector compares when size is 4 * CHAR_PER_VEC or less.
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+ 9. Use 8 vector compares when size is 8 * CHAR_PER_VEC or less. */
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# include <sysdep.h>
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@@ -40,11 +45,21 @@
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# define VMOVU vmovdqu64
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# ifdef USE_AS_WMEMCMP
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-# define VPCMPEQ vpcmpeqd
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+# define CHAR_SIZE 4
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+# define VPCMP vpcmpd
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# else
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-# define VPCMPEQ vpcmpeqb
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+# define CHAR_SIZE 1
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+# define VPCMP vpcmpub
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# endif
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+# define VEC_SIZE 32
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+# define PAGE_SIZE 4096
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+# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
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+
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+# define XMM0 xmm16
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+# define XMM1 xmm17
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+# define XMM2 xmm18
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+# define YMM0 ymm16
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# define XMM1 xmm17
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# define XMM2 xmm18
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# define YMM1 ymm17
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@@ -54,15 +69,6 @@
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# define YMM5 ymm21
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# define YMM6 ymm22
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-# define VEC_SIZE 32
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-# ifdef USE_AS_WMEMCMP
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-# define VEC_MASK 0xff
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-# define XMM_MASK 0xf
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-# else
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-# define VEC_MASK 0xffffffff
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-# define XMM_MASK 0xffff
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-# endif
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-
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/* Warning!
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wmemcmp has to use SIGNED comparison for elements.
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memcmp has to use UNSIGNED comparison for elemnts.
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@@ -70,145 +76,370 @@
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.section .text.evex,"ax",@progbits
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ENTRY (MEMCMP)
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-# ifdef USE_AS_WMEMCMP
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- shl $2, %RDX_LP
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-# elif defined __ILP32__
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+# ifdef __ILP32__
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/* Clear the upper 32 bits. */
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movl %edx, %edx
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# endif
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- cmp $VEC_SIZE, %RDX_LP
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+ cmp $CHAR_PER_VEC, %RDX_LP
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jb L(less_vec)
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/* From VEC to 2 * VEC. No branch when size == VEC_SIZE. */
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- VMOVU (%rsi), %YMM2
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- VPCMPEQ (%rdi), %YMM2, %k1
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+ VMOVU (%rsi), %YMM1
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+ /* Use compare not equals to directly check for mismatch. */
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+ VPCMP $4, (%rdi), %YMM1, %k1
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kmovd %k1, %eax
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- subl $VEC_MASK, %eax
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- jnz L(first_vec)
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-
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- cmpq $(VEC_SIZE * 2), %rdx
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- jbe L(last_vec)
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-
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- /* More than 2 * VEC. */
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- cmpq $(VEC_SIZE * 8), %rdx
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- ja L(more_8x_vec)
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- cmpq $(VEC_SIZE * 4), %rdx
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- jb L(last_4x_vec)
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+ /* NB: eax must be destination register if going to
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+ L(return_vec_[0,2]). For L(return_vec_3 destination register
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+ must be ecx. */
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+ testl %eax, %eax
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+ jnz L(return_vec_0)
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- /* From 4 * VEC to 8 * VEC, inclusively. */
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- VMOVU (%rsi), %YMM1
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- VPCMPEQ (%rdi), %YMM1, %k1
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+ cmpq $(CHAR_PER_VEC * 2), %rdx
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+ jbe L(last_1x_vec)
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+ /* Check second VEC no matter what. */
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VMOVU VEC_SIZE(%rsi), %YMM2
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- VPCMPEQ VEC_SIZE(%rdi), %YMM2, %k2
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+ VPCMP $4, VEC_SIZE(%rdi), %YMM2, %k1
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+ kmovd %k1, %eax
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+ testl %eax, %eax
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+ jnz L(return_vec_1)
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+
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+ /* Less than 4 * VEC. */
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+ cmpq $(CHAR_PER_VEC * 4), %rdx
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+ jbe L(last_2x_vec)
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+ /* Check third and fourth VEC no matter what. */
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VMOVU (VEC_SIZE * 2)(%rsi), %YMM3
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- VPCMPEQ (VEC_SIZE * 2)(%rdi), %YMM3, %k3
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+ VPCMP $4, (VEC_SIZE * 2)(%rdi), %YMM3, %k1
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+ kmovd %k1, %eax
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+ testl %eax, %eax
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+ jnz L(return_vec_2)
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VMOVU (VEC_SIZE * 3)(%rsi), %YMM4
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- VPCMPEQ (VEC_SIZE * 3)(%rdi), %YMM4, %k4
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+ VPCMP $4, (VEC_SIZE * 3)(%rdi), %YMM4, %k1
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+ kmovd %k1, %ecx
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+ testl %ecx, %ecx
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+ jnz L(return_vec_3)
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- kandd %k1, %k2, %k5
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- kandd %k3, %k4, %k6
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- kandd %k5, %k6, %k6
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+ /* Zero YMM0. 4x VEC reduction is done with vpxor + vtern so
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+ compare with zero to get a mask is needed. */
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+ vpxorq %XMM0, %XMM0, %XMM0
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- kmovd %k6, %eax
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- cmpl $VEC_MASK, %eax
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- jne L(4x_vec_end)
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+ /* Go to 4x VEC loop. */
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+ cmpq $(CHAR_PER_VEC * 8), %rdx
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+ ja L(more_8x_vec)
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- leaq -(4 * VEC_SIZE)(%rdi, %rdx), %rdi
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- leaq -(4 * VEC_SIZE)(%rsi, %rdx), %rsi
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- VMOVU (%rsi), %YMM1
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- VPCMPEQ (%rdi), %YMM1, %k1
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+ /* Handle remainder of size = 4 * VEC + 1 to 8 * VEC without any
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+ branches. */
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- VMOVU VEC_SIZE(%rsi), %YMM2
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- VPCMPEQ VEC_SIZE(%rdi), %YMM2, %k2
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- kandd %k1, %k2, %k5
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+ /* Load first two VEC from s2 before adjusting addresses. */
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+ VMOVU -(VEC_SIZE * 4)(%rsi, %rdx, CHAR_SIZE), %YMM1
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+ VMOVU -(VEC_SIZE * 3)(%rsi, %rdx, CHAR_SIZE), %YMM2
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+ leaq -(4 * VEC_SIZE)(%rdi, %rdx, CHAR_SIZE), %rdi
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+ leaq -(4 * VEC_SIZE)(%rsi, %rdx, CHAR_SIZE), %rsi
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+
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+ /* Wait to load from s1 until addressed adjust due to
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+ unlamination of microfusion with complex address mode. */
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+
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+ /* vpxor will be all 0s if s1 and s2 are equal. Otherwise it
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+ will have some 1s. */
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+ vpxorq (%rdi), %YMM1, %YMM1
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+ vpxorq (VEC_SIZE)(%rdi), %YMM2, %YMM2
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VMOVU (VEC_SIZE * 2)(%rsi), %YMM3
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- VPCMPEQ (VEC_SIZE * 2)(%rdi), %YMM3, %k3
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- kandd %k3, %k5, %k5
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+ vpxorq (VEC_SIZE * 2)(%rdi), %YMM3, %YMM3
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+ /* Or together YMM1, YMM2, and YMM3 into YMM3. */
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+ vpternlogd $0xfe, %YMM1, %YMM2, %YMM3
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VMOVU (VEC_SIZE * 3)(%rsi), %YMM4
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- VPCMPEQ (VEC_SIZE * 3)(%rdi), %YMM4, %k4
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- kandd %k4, %k5, %k5
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+ /* Ternary logic to xor (VEC_SIZE * 3)(%rdi) with YMM4 while
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+ oring with YMM3. Result is stored in YMM4. */
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+ vpternlogd $0xde, (VEC_SIZE * 3)(%rdi), %YMM3, %YMM4
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+ /* Compare YMM4 with 0. If any 1s s1 and s2 don't match. */
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+ VPCMP $4, %YMM4, %YMM0, %k1
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+ kmovd %k1, %ecx
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+ testl %ecx, %ecx
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+ jnz L(return_vec_0_1_2_3)
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+ /* NB: eax must be zero to reach here. */
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+ ret
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- kmovd %k5, %eax
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- cmpl $VEC_MASK, %eax
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- jne L(4x_vec_end)
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- xorl %eax, %eax
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+ /* NB: aligning 32 here allows for the rest of the jump targets
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+ to be tuned for 32 byte alignment. Most important this ensures
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+ the L(more_8x_vec) loop is 32 byte aligned. */
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+ .p2align 5
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+L(less_vec):
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+ /* Check if one or less CHAR. This is necessary for size = 0 but
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+ is also faster for size = CHAR_SIZE. */
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+ cmpl $1, %edx
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+ jbe L(one_or_less)
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+
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+ /* Check if loading one VEC from either s1 or s2 could cause a
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+ page cross. This can have false positives but is by far the
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+ fastest method. */
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+ movl %edi, %eax
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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), %eax
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+ jg L(page_cross_less_vec)
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+
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+ /* No page cross possible. */
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+ VMOVU (%rsi), %YMM2
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+ VPCMP $4, (%rdi), %YMM2, %k1
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+ kmovd %k1, %eax
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+ /* Create mask in ecx for potentially in bound matches. */
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+ bzhil %edx, %eax, %eax
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+ jnz L(return_vec_0)
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ret
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.p2align 4
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-L(last_2x_vec):
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- /* From VEC to 2 * VEC. No branch when size == VEC_SIZE. */
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- VMOVU (%rsi), %YMM2
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- VPCMPEQ (%rdi), %YMM2, %k2
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- kmovd %k2, %eax
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- subl $VEC_MASK, %eax
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- jnz L(first_vec)
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+L(return_vec_0):
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+ tzcntl %eax, %eax
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+# ifdef USE_AS_WMEMCMP
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+ movl (%rdi, %rax, CHAR_SIZE), %ecx
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+ xorl %edx, %edx
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+ cmpl (%rsi, %rax, CHAR_SIZE), %ecx
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+ /* NB: no partial register stall here because xorl zero idiom
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+ above. */
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+ setg %dl
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+ leal -1(%rdx, %rdx), %eax
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+# else
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+ movzbl (%rsi, %rax), %ecx
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+ movzbl (%rdi, %rax), %eax
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+ subl %ecx, %eax
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+# endif
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+ ret
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-L(last_vec):
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- /* Use overlapping loads to avoid branches. */
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- leaq -VEC_SIZE(%rdi, %rdx), %rdi
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- leaq -VEC_SIZE(%rsi, %rdx), %rsi
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- VMOVU (%rsi), %YMM2
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- VPCMPEQ (%rdi), %YMM2, %k2
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- kmovd %k2, %eax
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- subl $VEC_MASK, %eax
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- jnz L(first_vec)
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+ /* NB: No p2align necessary. Alignment % 16 is naturally 1
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+ which is good enough for a target not in a loop. */
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+L(return_vec_1):
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+ tzcntl %eax, %eax
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+# ifdef USE_AS_WMEMCMP
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+ movl VEC_SIZE(%rdi, %rax, CHAR_SIZE), %ecx
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+ xorl %edx, %edx
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+ cmpl VEC_SIZE(%rsi, %rax, CHAR_SIZE), %ecx
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+ setg %dl
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+ leal -1(%rdx, %rdx), %eax
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+# else
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+ movzbl VEC_SIZE(%rsi, %rax), %ecx
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+ movzbl VEC_SIZE(%rdi, %rax), %eax
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+ subl %ecx, %eax
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+# endif
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ret
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- .p2align 4
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-L(first_vec):
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- /* A byte or int32 is different within 16 or 32 bytes. */
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- tzcntl %eax, %ecx
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+ /* NB: No p2align necessary. Alignment % 16 is naturally 2
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+ which is good enough for a target not in a loop. */
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+L(return_vec_2):
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+ tzcntl %eax, %eax
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# ifdef USE_AS_WMEMCMP
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- xorl %eax, %eax
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- movl (%rdi, %rcx, 4), %edx
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- cmpl (%rsi, %rcx, 4), %edx
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-L(wmemcmp_return):
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- setl %al
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- negl %eax
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- orl $1, %eax
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+ movl (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %ecx
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+ xorl %edx, %edx
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+ cmpl (VEC_SIZE * 2)(%rsi, %rax, CHAR_SIZE), %ecx
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+ setg %dl
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+ leal -1(%rdx, %rdx), %eax
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# else
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- movzbl (%rdi, %rcx), %eax
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- movzbl (%rsi, %rcx), %edx
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- sub %edx, %eax
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+ movzbl (VEC_SIZE * 2)(%rsi, %rax), %ecx
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+ movzbl (VEC_SIZE * 2)(%rdi, %rax), %eax
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+ subl %ecx, %eax
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# endif
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ret
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+ .p2align 4
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+L(8x_return_vec_0_1_2_3):
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+ /* Returning from L(more_8x_vec) requires restoring rsi. */
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+ addq %rdi, %rsi
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+L(return_vec_0_1_2_3):
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+ VPCMP $4, %YMM1, %YMM0, %k0
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+ kmovd %k0, %eax
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+ testl %eax, %eax
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+ jnz L(return_vec_0)
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+
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+ VPCMP $4, %YMM2, %YMM0, %k0
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+ kmovd %k0, %eax
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+ testl %eax, %eax
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+ jnz L(return_vec_1)
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+
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+ VPCMP $4, %YMM3, %YMM0, %k0
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+ kmovd %k0, %eax
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+ testl %eax, %eax
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+ jnz L(return_vec_2)
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+L(return_vec_3):
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+ tzcntl %ecx, %ecx
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# ifdef USE_AS_WMEMCMP
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+ movl (VEC_SIZE * 3)(%rdi, %rcx, CHAR_SIZE), %eax
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+ xorl %edx, %edx
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+ cmpl (VEC_SIZE * 3)(%rsi, %rcx, CHAR_SIZE), %eax
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+ setg %dl
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+ leal -1(%rdx, %rdx), %eax
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+# else
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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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+ ret
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+
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.p2align 4
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-L(4):
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- xorl %eax, %eax
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- movl (%rdi), %edx
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- cmpl (%rsi), %edx
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- jne L(wmemcmp_return)
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+L(more_8x_vec):
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+ /* Set end of s1 in rdx. */
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+ leaq -(VEC_SIZE * 4)(%rdi, %rdx, CHAR_SIZE), %rdx
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+ /* rsi stores s2 - s1. This allows loop to only update one
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+ pointer. */
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+ subq %rdi, %rsi
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+ /* Align s1 pointer. */
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+ andq $-VEC_SIZE, %rdi
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+ /* Adjust because first 4x vec where check already. */
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+ subq $-(VEC_SIZE * 4), %rdi
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+ .p2align 4
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+L(loop_4x_vec):
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+ VMOVU (%rsi, %rdi), %YMM1
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+ vpxorq (%rdi), %YMM1, %YMM1
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+
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+ VMOVU VEC_SIZE(%rsi, %rdi), %YMM2
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+ vpxorq VEC_SIZE(%rdi), %YMM2, %YMM2
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+
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+ VMOVU (VEC_SIZE * 2)(%rsi, %rdi), %YMM3
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+ vpxorq (VEC_SIZE * 2)(%rdi), %YMM3, %YMM3
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+ vpternlogd $0xfe, %YMM1, %YMM2, %YMM3
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+
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+ VMOVU (VEC_SIZE * 3)(%rsi, %rdi), %YMM4
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+ vpternlogd $0xde, (VEC_SIZE * 3)(%rdi), %YMM3, %YMM4
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+ VPCMP $4, %YMM4, %YMM0, %k1
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+ kmovd %k1, %ecx
|
|
+ testl %ecx, %ecx
|
|
+ jnz L(8x_return_vec_0_1_2_3)
|
|
+ subq $-(VEC_SIZE * 4), %rdi
|
|
+ cmpq %rdx, %rdi
|
|
+ jb L(loop_4x_vec)
|
|
+
|
|
+ subq %rdx, %rdi
|
|
+ /* rdi has 4 * VEC_SIZE - remaining length. */
|
|
+ cmpl $(VEC_SIZE * 3), %edi
|
|
+ jae L(8x_last_1x_vec)
|
|
+ /* Load regardless of branch. */
|
|
+ VMOVU (VEC_SIZE * 2)(%rsi, %rdx), %YMM3
|
|
+ cmpl $(VEC_SIZE * 2), %edi
|
|
+ jae L(8x_last_2x_vec)
|
|
+
|
|
+ VMOVU (%rsi, %rdx), %YMM1
|
|
+ vpxorq (%rdx), %YMM1, %YMM1
|
|
+
|
|
+ VMOVU VEC_SIZE(%rsi, %rdx), %YMM2
|
|
+ vpxorq VEC_SIZE(%rdx), %YMM2, %YMM2
|
|
+
|
|
+ vpxorq (VEC_SIZE * 2)(%rdx), %YMM3, %YMM3
|
|
+ vpternlogd $0xfe, %YMM1, %YMM2, %YMM3
|
|
+
|
|
+ VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %YMM4
|
|
+ vpternlogd $0xde, (VEC_SIZE * 3)(%rdx), %YMM3, %YMM4
|
|
+ VPCMP $4, %YMM4, %YMM0, %k1
|
|
+ kmovd %k1, %ecx
|
|
+ /* Restore s1 pointer to rdi. */
|
|
+ movq %rdx, %rdi
|
|
+ testl %ecx, %ecx
|
|
+ jnz L(8x_return_vec_0_1_2_3)
|
|
+ /* NB: eax must be zero to reach here. */
|
|
+ ret
|
|
+
|
|
+ /* Only entry is from L(more_8x_vec). */
|
|
+ .p2align 4
|
|
+L(8x_last_2x_vec):
|
|
+ VPCMP $4, (VEC_SIZE * 2)(%rdx), %YMM3, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(8x_return_vec_2)
|
|
+ /* Naturally aligned to 16 bytes. */
|
|
+L(8x_last_1x_vec):
|
|
+ VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %YMM1
|
|
+ VPCMP $4, (VEC_SIZE * 3)(%rdx), %YMM1, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(8x_return_vec_3)
|
|
+ ret
|
|
+
|
|
+ .p2align 4
|
|
+L(last_2x_vec):
|
|
+ /* Check second to last VEC. */
|
|
+ VMOVU -(VEC_SIZE * 2)(%rsi, %rdx, CHAR_SIZE), %YMM1
|
|
+ VPCMP $4, -(VEC_SIZE * 2)(%rdi, %rdx, CHAR_SIZE), %YMM1, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_1_end)
|
|
+
|
|
+ /* Check last VEC. */
|
|
+ .p2align 4
|
|
+L(last_1x_vec):
|
|
+ VMOVU -(VEC_SIZE * 1)(%rsi, %rdx, CHAR_SIZE), %YMM1
|
|
+ VPCMP $4, -(VEC_SIZE * 1)(%rdi, %rdx, CHAR_SIZE), %YMM1, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_0_end)
|
|
ret
|
|
+
|
|
+ .p2align 4
|
|
+L(8x_return_vec_2):
|
|
+ subq $VEC_SIZE, %rdx
|
|
+L(8x_return_vec_3):
|
|
+ tzcntl %eax, %eax
|
|
+# ifdef USE_AS_WMEMCMP
|
|
+ leaq (%rdx, %rax, CHAR_SIZE), %rax
|
|
+ movl (VEC_SIZE * 3)(%rax), %ecx
|
|
+ xorl %edx, %edx
|
|
+ cmpl (VEC_SIZE * 3)(%rsi, %rax), %ecx
|
|
+ setg %dl
|
|
+ leal -1(%rdx, %rdx), %eax
|
|
# else
|
|
+ addq %rdx, %rax
|
|
+ movzbl (VEC_SIZE * 3)(%rsi, %rax), %ecx
|
|
+ movzbl (VEC_SIZE * 3)(%rax), %eax
|
|
+ subl %ecx, %eax
|
|
+# endif
|
|
+ ret
|
|
+
|
|
.p2align 4
|
|
-L(between_4_7):
|
|
- /* Load as big endian with overlapping movbe to avoid branches. */
|
|
- movbe (%rdi), %eax
|
|
- movbe (%rsi), %ecx
|
|
- shlq $32, %rax
|
|
- shlq $32, %rcx
|
|
- movbe -4(%rdi, %rdx), %edi
|
|
- movbe -4(%rsi, %rdx), %esi
|
|
- orq %rdi, %rax
|
|
- orq %rsi, %rcx
|
|
- subq %rcx, %rax
|
|
- je L(exit)
|
|
- sbbl %eax, %eax
|
|
- orl $1, %eax
|
|
+L(return_vec_0_end):
|
|
+ tzcntl %eax, %eax
|
|
+ addl %edx, %eax
|
|
+# ifdef USE_AS_WMEMCMP
|
|
+ movl -VEC_SIZE(%rdi, %rax, CHAR_SIZE), %ecx
|
|
+ xorl %edx, %edx
|
|
+ cmpl -VEC_SIZE(%rsi, %rax, CHAR_SIZE), %ecx
|
|
+ setg %dl
|
|
+ leal -1(%rdx, %rdx), %eax
|
|
+# else
|
|
+ movzbl -VEC_SIZE(%rsi, %rax), %ecx
|
|
+ movzbl -VEC_SIZE(%rdi, %rax), %eax
|
|
+ subl %ecx, %eax
|
|
+# endif
|
|
ret
|
|
|
|
.p2align 4
|
|
-L(exit):
|
|
+L(return_vec_1_end):
|
|
+ tzcntl %eax, %eax
|
|
+ addl %edx, %eax
|
|
+# ifdef USE_AS_WMEMCMP
|
|
+ movl -(VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %ecx
|
|
+ xorl %edx, %edx
|
|
+ cmpl -(VEC_SIZE * 2)(%rsi, %rax, CHAR_SIZE), %ecx
|
|
+ setg %dl
|
|
+ leal -1(%rdx, %rdx), %eax
|
|
+# else
|
|
+ movzbl -(VEC_SIZE * 2)(%rsi, %rax), %ecx
|
|
+ movzbl -(VEC_SIZE * 2)(%rdi, %rax), %eax
|
|
+ subl %ecx, %eax
|
|
+# endif
|
|
ret
|
|
|
|
+
|
|
.p2align 4
|
|
+L(page_cross_less_vec):
|
|
+ /* if USE_AS_WMEMCMP it can only be 0, 4, 8, 12, 16, 20, 24, 28
|
|
+ bytes. */
|
|
+ cmpl $(16 / CHAR_SIZE), %edx
|
|
+ jae L(between_16_31)
|
|
+# ifndef USE_AS_WMEMCMP
|
|
+ cmpl $8, %edx
|
|
+ jae L(between_8_15)
|
|
+ cmpl $4, %edx
|
|
+ jae L(between_4_7)
|
|
L(between_2_3):
|
|
/* Load as big endian to avoid branches. */
|
|
movzwl (%rdi), %eax
|
|
@@ -217,224 +448,99 @@ L(between_2_3):
|
|
shll $8, %ecx
|
|
bswap %eax
|
|
bswap %ecx
|
|
- movb -1(%rdi, %rdx), %al
|
|
- movb -1(%rsi, %rdx), %cl
|
|
+ movzbl -1(%rdi, %rdx), %edi
|
|
+ movzbl -1(%rsi, %rdx), %esi
|
|
+ orl %edi, %eax
|
|
+ orl %esi, %ecx
|
|
/* Subtraction is okay because the upper 8 bits are zero. */
|
|
subl %ecx, %eax
|
|
ret
|
|
-
|
|
.p2align 4
|
|
-L(1):
|
|
- movzbl (%rdi), %eax
|
|
+L(one_or_less):
|
|
+ jb L(zero)
|
|
movzbl (%rsi), %ecx
|
|
+ movzbl (%rdi), %eax
|
|
subl %ecx, %eax
|
|
ret
|
|
-# endif
|
|
-
|
|
- .p2align 4
|
|
-L(zero):
|
|
- xorl %eax, %eax
|
|
- ret
|
|
|
|
.p2align 4
|
|
-L(less_vec):
|
|
-# ifdef USE_AS_WMEMCMP
|
|
- /* It can only be 0, 4, 8, 12, 16, 20, 24, 28 bytes. */
|
|
- cmpb $4, %dl
|
|
- je L(4)
|
|
- jb L(zero)
|
|
-# else
|
|
- cmpb $1, %dl
|
|
- je L(1)
|
|
- jb L(zero)
|
|
- cmpb $4, %dl
|
|
- jb L(between_2_3)
|
|
- cmpb $8, %dl
|
|
- jb L(between_4_7)
|
|
+L(between_8_15):
|
|
# endif
|
|
- cmpb $16, %dl
|
|
- jae L(between_16_31)
|
|
- /* It is between 8 and 15 bytes. */
|
|
+ /* If USE_AS_WMEMCMP fall through into 8-15 byte case. */
|
|
vmovq (%rdi), %XMM1
|
|
vmovq (%rsi), %XMM2
|
|
- VPCMPEQ %XMM1, %XMM2, %k2
|
|
- kmovw %k2, %eax
|
|
- subl $XMM_MASK, %eax
|
|
- jnz L(first_vec)
|
|
+ VPCMP $4, %XMM1, %XMM2, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_0)
|
|
/* Use overlapping loads to avoid branches. */
|
|
- leaq -8(%rdi, %rdx), %rdi
|
|
- leaq -8(%rsi, %rdx), %rsi
|
|
+ leaq -8(%rdi, %rdx, CHAR_SIZE), %rdi
|
|
+ leaq -8(%rsi, %rdx, CHAR_SIZE), %rsi
|
|
vmovq (%rdi), %XMM1
|
|
vmovq (%rsi), %XMM2
|
|
- VPCMPEQ %XMM1, %XMM2, %k2
|
|
- kmovw %k2, %eax
|
|
- subl $XMM_MASK, %eax
|
|
- jnz L(first_vec)
|
|
+ VPCMP $4, %XMM1, %XMM2, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_0)
|
|
ret
|
|
|
|
.p2align 4
|
|
-L(between_16_31):
|
|
- /* From 16 to 31 bytes. No branch when size == 16. */
|
|
- VMOVU (%rsi), %XMM2
|
|
- VPCMPEQ (%rdi), %XMM2, %k2
|
|
- kmovw %k2, %eax
|
|
- subl $XMM_MASK, %eax
|
|
- jnz L(first_vec)
|
|
-
|
|
- /* Use overlapping loads to avoid branches. */
|
|
- leaq -16(%rdi, %rdx), %rdi
|
|
- leaq -16(%rsi, %rdx), %rsi
|
|
- VMOVU (%rsi), %XMM2
|
|
- VPCMPEQ (%rdi), %XMM2, %k2
|
|
- kmovw %k2, %eax
|
|
- subl $XMM_MASK, %eax
|
|
- jnz L(first_vec)
|
|
+L(zero):
|
|
+ xorl %eax, %eax
|
|
ret
|
|
|
|
.p2align 4
|
|
-L(more_8x_vec):
|
|
- /* More than 8 * VEC. Check the first VEC. */
|
|
- VMOVU (%rsi), %YMM2
|
|
- VPCMPEQ (%rdi), %YMM2, %k2
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
-
|
|
- /* Align the first memory area for aligned loads in the loop.
|
|
- Compute how much the first memory area is misaligned. */
|
|
- movq %rdi, %rcx
|
|
- andl $(VEC_SIZE - 1), %ecx
|
|
- /* Get the negative of offset for alignment. */
|
|
- subq $VEC_SIZE, %rcx
|
|
- /* Adjust the second memory area. */
|
|
- subq %rcx, %rsi
|
|
- /* Adjust the first memory area which should be aligned now. */
|
|
- subq %rcx, %rdi
|
|
- /* Adjust length. */
|
|
- addq %rcx, %rdx
|
|
-
|
|
-L(loop_4x_vec):
|
|
- /* Compare 4 * VEC at a time forward. */
|
|
- VMOVU (%rsi), %YMM1
|
|
- VPCMPEQ (%rdi), %YMM1, %k1
|
|
-
|
|
- VMOVU VEC_SIZE(%rsi), %YMM2
|
|
- VPCMPEQ VEC_SIZE(%rdi), %YMM2, %k2
|
|
- kandd %k2, %k1, %k5
|
|
-
|
|
- VMOVU (VEC_SIZE * 2)(%rsi), %YMM3
|
|
- VPCMPEQ (VEC_SIZE * 2)(%rdi), %YMM3, %k3
|
|
- kandd %k3, %k5, %k5
|
|
-
|
|
- VMOVU (VEC_SIZE * 3)(%rsi), %YMM4
|
|
- VPCMPEQ (VEC_SIZE * 3)(%rdi), %YMM4, %k4
|
|
- kandd %k4, %k5, %k5
|
|
-
|
|
- kmovd %k5, %eax
|
|
- cmpl $VEC_MASK, %eax
|
|
- jne L(4x_vec_end)
|
|
-
|
|
- addq $(VEC_SIZE * 4), %rdi
|
|
- addq $(VEC_SIZE * 4), %rsi
|
|
-
|
|
- subq $(VEC_SIZE * 4), %rdx
|
|
- cmpq $(VEC_SIZE * 4), %rdx
|
|
- jae L(loop_4x_vec)
|
|
-
|
|
- /* Less than 4 * VEC. */
|
|
- cmpq $VEC_SIZE, %rdx
|
|
- jbe L(last_vec)
|
|
- cmpq $(VEC_SIZE * 2), %rdx
|
|
- jbe L(last_2x_vec)
|
|
-
|
|
-L(last_4x_vec):
|
|
- /* From 2 * VEC to 4 * VEC. */
|
|
- VMOVU (%rsi), %YMM2
|
|
- VPCMPEQ (%rdi), %YMM2, %k2
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
-
|
|
- addq $VEC_SIZE, %rdi
|
|
- addq $VEC_SIZE, %rsi
|
|
- VMOVU (%rsi), %YMM2
|
|
- VPCMPEQ (%rdi), %YMM2, %k2
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
+L(between_16_31):
|
|
+ /* From 16 to 31 bytes. No branch when size == 16. */
|
|
+ VMOVU (%rsi), %XMM2
|
|
+ VPCMP $4, (%rdi), %XMM2, %k1
|
|
+ kmovd %k1, %eax
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_0)
|
|
|
|
/* Use overlapping loads to avoid branches. */
|
|
- leaq -(3 * VEC_SIZE)(%rdi, %rdx), %rdi
|
|
- leaq -(3 * VEC_SIZE)(%rsi, %rdx), %rsi
|
|
- VMOVU (%rsi), %YMM2
|
|
- VPCMPEQ (%rdi), %YMM2, %k2
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
|
|
- addq $VEC_SIZE, %rdi
|
|
- addq $VEC_SIZE, %rsi
|
|
- VMOVU (%rsi), %YMM2
|
|
- VPCMPEQ (%rdi), %YMM2, %k2
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
- ret
|
|
-
|
|
- .p2align 4
|
|
-L(4x_vec_end):
|
|
+ VMOVU -16(%rsi, %rdx, CHAR_SIZE), %XMM2
|
|
+ leaq -16(%rdi, %rdx, CHAR_SIZE), %rdi
|
|
+ leaq -16(%rsi, %rdx, CHAR_SIZE), %rsi
|
|
+ VPCMP $4, (%rdi), %XMM2, %k1
|
|
kmovd %k1, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec)
|
|
- kmovd %k2, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec_x1)
|
|
- kmovd %k3, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- jnz L(first_vec_x2)
|
|
- kmovd %k4, %eax
|
|
- subl $VEC_MASK, %eax
|
|
- tzcntl %eax, %ecx
|
|
-# ifdef USE_AS_WMEMCMP
|
|
- xorl %eax, %eax
|
|
- movl (VEC_SIZE * 3)(%rdi, %rcx, 4), %edx
|
|
- cmpl (VEC_SIZE * 3)(%rsi, %rcx, 4), %edx
|
|
- jmp L(wmemcmp_return)
|
|
-# else
|
|
- movzbl (VEC_SIZE * 3)(%rdi, %rcx), %eax
|
|
- movzbl (VEC_SIZE * 3)(%rsi, %rcx), %edx
|
|
- sub %edx, %eax
|
|
-# endif
|
|
+ testl %eax, %eax
|
|
+ jnz L(return_vec_0)
|
|
ret
|
|
|
|
- .p2align 4
|
|
-L(first_vec_x1):
|
|
- tzcntl %eax, %ecx
|
|
# ifdef USE_AS_WMEMCMP
|
|
- xorl %eax, %eax
|
|
- movl VEC_SIZE(%rdi, %rcx, 4), %edx
|
|
- cmpl VEC_SIZE(%rsi, %rcx, 4), %edx
|
|
- jmp L(wmemcmp_return)
|
|
-# else
|
|
- movzbl VEC_SIZE(%rdi, %rcx), %eax
|
|
- movzbl VEC_SIZE(%rsi, %rcx), %edx
|
|
- sub %edx, %eax
|
|
-# endif
|
|
+ .p2align 4
|
|
+L(one_or_less):
|
|
+ jb L(zero)
|
|
+ movl (%rdi), %ecx
|
|
+ xorl %edx, %edx
|
|
+ cmpl (%rsi), %ecx
|
|
+ je L(zero)
|
|
+ setg %dl
|
|
+ leal -1(%rdx, %rdx), %eax
|
|
ret
|
|
+# else
|
|
|
|
.p2align 4
|
|
-L(first_vec_x2):
|
|
- tzcntl %eax, %ecx
|
|
-# ifdef USE_AS_WMEMCMP
|
|
- xorl %eax, %eax
|
|
- movl (VEC_SIZE * 2)(%rdi, %rcx, 4), %edx
|
|
- cmpl (VEC_SIZE * 2)(%rsi, %rcx, 4), %edx
|
|
- jmp L(wmemcmp_return)
|
|
-# else
|
|
- movzbl (VEC_SIZE * 2)(%rdi, %rcx), %eax
|
|
- movzbl (VEC_SIZE * 2)(%rsi, %rcx), %edx
|
|
- sub %edx, %eax
|
|
-# endif
|
|
+L(between_4_7):
|
|
+ /* Load as big endian with overlapping movbe to avoid branches.
|
|
+ */
|
|
+ movbe (%rdi), %eax
|
|
+ movbe (%rsi), %ecx
|
|
+ shlq $32, %rax
|
|
+ shlq $32, %rcx
|
|
+ movbe -4(%rdi, %rdx), %edi
|
|
+ movbe -4(%rsi, %rdx), %esi
|
|
+ orq %rdi, %rax
|
|
+ orq %rsi, %rcx
|
|
+ subq %rcx, %rax
|
|
+ jz L(zero_4_7)
|
|
+ sbbl %eax, %eax
|
|
+ orl $1, %eax
|
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+L(zero_4_7):
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ret
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+# endif
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|
+
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END (MEMCMP)
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#endif
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--
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GitLab
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|