Attachment 5264 Details for Bug 12518 – Example patch to give the basic idea

[patch] Example patch to give the basic idea

patch.diff (text/plain), 3.78 KB, created by Linus Torvalds on 2011-02-25 02:26:20 UTC

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Creator: Linus Torvalds

Created: 2011-02-25 02:26:20 UTC

Size: 3.78 KB

patch

obsolete

> sysdeps/x86_64/multiarch/memcpy-ssse3.S  |   48 +++++++++++++++---------------
> sysdeps/x86_64/multiarch/memmove-ssse3.S |    8 ++--
> 2 files changed, 28 insertions(+), 28 deletions(-)
>
>diff --git a/sysdeps/x86_64/multiarch/memcpy-ssse3.S b/sysdeps/x86_64/multiarch/memcpy-ssse3.S
>index 9a878d3..747d2ef 100644
>--- a/sysdeps/x86_64/multiarch/memcpy-ssse3.S
>+++ b/sysdeps/x86_64/multiarch/memcpy-ssse3.S
>@@ -61,18 +61,15 @@ ENTRY (MEMCPY)
> #ifdef USE_AS_MEMPCPY
> 	add	%rdx, %rax
> #endif
>-
>-#ifdef USE_AS_MEMMOVE
>-	cmp	%rsi, %rdi
>-	jb	L(copy_forward)
>-	je	L(write_0bytes)
>-	cmp	$79, %rdx
>-	jbe	L(copy_forward)
>-	jmp	L(copy_backward)
>-L(copy_forward):
>-#endif
>-	cmp	$79, %rdx
>-	lea     L(table_less_80bytes)(%rip), %r11
>+	/*
>+	 * The small cases we can do without checking for any
>+	 * overlap at all, since we do them as all loads followed
>+	 * by all stores.
>+	 *
>+	 * So just jump through the less-than-80bytes table.
>+	 */
>+	cmp	$79,%rdx
>+	lea	L(table_less_80bytes)(%rip), %r11
> 	ja	L(80bytesormore)
> 	movslq	(%r11, %rdx, 4), %r9
> 	add	%rdx, %rsi
>@@ -81,13 +78,24 @@ L(copy_forward):
> 	jmp	*%r9
> 	ud2
> 
>-	ALIGN (4)
>+	/*
>+	 * For the 80+ byte cases we need to check overlap
>+	 */
> L(80bytesormore):
>-#ifndef USE_AS_MEMMOVE
>+	lea	(%rsi,%rdx),%r9
>+	lea	(%rdi,%rdx),%r11
>+	cmp	%rdi,%r9		/* dest start >= source end */
>+	jae	L(nonoverlap)		/*  -> nonoverlapping */
>+	cmp	%rsi,%r11		/* source start >= destination end */
>+	jae	L(nonoverlap)		/*  -> nonoverlapping */
>+	cmp	%rsi, %rdi		/* overlap: */
>+	jb	L(copy_forward)		/* source < dest: forward copy */
>+	je	L(write_0bytes)		/* source == dest: no copy */
>+	jmp	L(copy_backward)	/* source > dest: backward copy */
>+L(nonoverlap):
> 	cmp	%dil, %sil
> 	jle	L(copy_backward)
>-#endif
>-
>+L(copy_forward):
> 	movdqu	(%rsi), %xmm0
> 	mov	%rdi, %rcx
> 	and	$-16, %rdi
>@@ -2805,7 +2813,6 @@ L(large_page_fwd):
> 	movntdq	%xmm1, (%rdi)
> 	lea	16(%rdi), %rdi
> 	lea	-0x90(%rdx), %rdx
>-#ifdef USE_AS_MEMMOVE
> 	mov	%rsi, %r9
> 	sub	%rdi, %r9
> 	cmp	%rdx, %r9
>@@ -2814,7 +2821,6 @@ L(large_page_fwd):
> 	cmp	%rcx, %rdx
> 	jb	L(ll_cache_copy_fwd_start)
> L(memmove_is_memcpy_fwd):
>-#endif
> L(large_page_loop):
> 	movdqu	(%rsi), %xmm0
> 	movdqu	0x10(%rsi), %xmm1
>@@ -2859,7 +2865,6 @@ L(large_page_less_64bytes):
> 	sfence
> 	BRANCH_TO_JMPTBL_ENTRY (L(table_less_80bytes), %rdx, 4)
> 
>-#ifdef USE_AS_MEMMOVE
> 	ALIGN (4)
> L(ll_cache_copy_fwd_start):
> 	prefetcht0 0x1c0(%rsi)
>@@ -2906,7 +2911,6 @@ L(large_page_ll_less_fwd_64bytes):
> 	add	%rdx, %rdi
> 	BRANCH_TO_JMPTBL_ENTRY (L(table_less_80bytes), %rdx, 4)
> 
>-#endif
> 	ALIGN (4)
> L(large_page_bwd):
> 	movdqu	-0x10(%rsi), %xmm1
>@@ -2915,7 +2919,6 @@ L(large_page_bwd):
> 	movdqa	%xmm1, -0x10(%rdi)
> 	lea	-16(%rdi), %rdi
> 	lea	-0x90(%rdx), %rdx
>-#ifdef USE_AS_MEMMOVE
> 	mov	%rdi, %r9
> 	sub	%rsi, %r9
> 	cmp	%rdx, %r9
>@@ -2923,7 +2926,6 @@ L(large_page_bwd):
> 	cmp	%rcx, %r9
> 	jb	L(ll_cache_copy_bwd_start)
> L(memmove_is_memcpy_bwd):
>-#endif
> L(large_page_bwd_loop):
> 	movdqu	-0x10(%rsi), %xmm0
> 	movdqu	-0x20(%rsi), %xmm1
>@@ -2966,7 +2968,6 @@ L(large_page_less_bwd_64bytes):
> 	sfence
> 	BRANCH_TO_JMPTBL_ENTRY (L(table_less_80bytes), %rdx, 4)
> 
>-#ifdef USE_AS_MEMMOVE
> 	ALIGN (4)
> L(ll_cache_copy_bwd_start):
> 	prefetcht0 -0x1c0(%rsi)
>@@ -3010,7 +3011,6 @@ L(ll_cache_copy_bwd_start):
> 	sub	$0x40, %rdx
> L(large_page_ll_less_bwd_64bytes):
> 	BRANCH_TO_JMPTBL_ENTRY (L(table_less_80bytes), %rdx, 4)
>-#endif
> 
> END (MEMCPY)
> 
>diff --git a/sysdeps/x86_64/multiarch/memmove-ssse3.S b/sysdeps/x86_64/multiarch/memmove-ssse3.S
>index 295430b..a38d445 100644
>--- a/sysdeps/x86_64/multiarch/memmove-ssse3.S
>+++ b/sysdeps/x86_64/multiarch/memmove-ssse3.S
>@@ -1,4 +1,4 @@
>-#define USE_AS_MEMMOVE
>-#define MEMCPY		__memmove_ssse3
>-#define MEMCPY_CHK	__memmove_chk_ssse3
>-#include "memcpy-ssse3.S"
>+#include <sysdep.h>
>+
>+strong_alias(__memmove_ssse3, __memcpy_ssse3);
>+strong_alias(__memmove_chk_ssse3, __memcpy_chk_ssse3);

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Attachments on bug 12518: 5264 | 5323 | 5341 | 5660