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-rw-r--r--arch/x86/lib/memmove_64.S7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/lib/memmove_64.S b/arch/x86/lib/memmove_64.S
index 337830d7a59c..7ff00ea64e4f 100644
--- a/arch/x86/lib/memmove_64.S
+++ b/arch/x86/lib/memmove_64.S
@@ -29,10 +29,7 @@
SYM_FUNC_START_ALIAS(memmove)
SYM_FUNC_START(__memmove)
- /* Handle more 32 bytes in loop */
mov %rdi, %rax
- cmp $0x20, %rdx
- jb 1f
/* Decide forward/backward copy mode */
cmp %rdi, %rsi
@@ -42,7 +39,9 @@ SYM_FUNC_START(__memmove)
cmp %rdi, %r8
jg 2f
+ /* FSRM implies ERMS => no length checks, do the copy directly */
.Lmemmove_begin_forward:
+ ALTERNATIVE "cmp $0x20, %rdx; jb 1f", "", X86_FEATURE_FSRM
ALTERNATIVE "", "movq %rdx, %rcx; rep movsb; retq", X86_FEATURE_ERMS
/*
@@ -114,6 +113,8 @@ SYM_FUNC_START(__memmove)
*/
.p2align 4
2:
+ cmp $0x20, %rdx
+ jb 1f
cmp $680, %rdx
jb 6f
cmp %dil, %sil

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