Author: kib
Date: Thu Jan 11 13:22:13 2018
New Revision: 327820
URL: https://svnweb.freebsd.org/changeset/base/327820
Log:
Remove redundand CLD instructions.
We already clear %RFLAGS.DF on the kernel entry due to the compiler's
ABI requirements.
Suggested by: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/amd64/amd64/support.S
head/sys/i386/i386/support.s
Modified: head/sys/amd64/amd64/support.S
==============================================================================
--- head/sys/amd64/amd64/support.S Thu Jan 11 12:54:33 2018
(r327819)
+++ head/sys/amd64/amd64/support.S Thu Jan 11 13:22:13 2018
(r327820)
@@ -50,7 +50,6 @@ ENTRY(bzero)
movq %rsi,%rcx
xorl %eax,%eax
shrq $3,%rcx
- cld
rep
stosq
movq %rsi,%rcx
@@ -100,7 +99,6 @@ ENTRY(bcmp)
PUSH_FRAME_POINTER
movq %rdx,%rcx
shrq $3,%rcx
- cld /* compare forwards */
repe
cmpsq
jne 1f
@@ -132,7 +130,6 @@ ENTRY(bcopy)
jb 1f
shrq $3,%rcx /* copy by 64-bit words */
- cld /* nope, copy forwards */
rep
movsq
movq %rdx,%rcx
@@ -171,7 +168,6 @@ ENTRY(memcpy)
movq %rdi,%rax
movq %rdx,%rcx
shrq $3,%rcx /* copy by 64-bit words */
- cld /* copy forwards */
rep
movsq
movq %rdx,%rcx
@@ -218,7 +214,6 @@ ENTRY(fillw)
movq %rdi,%rax
movq %rsi,%rdi
movq %rdx,%rcx
- cld
rep
stosw
POP_FRAME_POINTER
@@ -274,7 +269,6 @@ ENTRY(copyout)
movq %rdx,%rcx
shrq $3,%rcx
- cld
rep
movsq
movb %dl,%cl
@@ -323,7 +317,6 @@ ENTRY(copyin)
movq %rdx,%rcx
movb %cl,%al
shrq $3,%rcx /* copy longword-wise */
- cld
rep
movsq
movb %al,%cl
@@ -620,7 +613,6 @@ ENTRY(copyinstr)
movq %rax,%r8
1:
incq %rdx
- cld
2:
decq %rdx
@@ -671,7 +663,6 @@ ENTRY(copystr)
xchgq %rdi,%rsi
incq %rdx
- cld
1:
decq %rdx
jz 4f
Modified: head/sys/i386/i386/support.s
==============================================================================
--- head/sys/i386/i386/support.s Thu Jan 11 12:54:33 2018
(r327819)
+++ head/sys/i386/i386/support.s Thu Jan 11 13:22:13 2018
(r327820)
@@ -50,7 +50,6 @@ ENTRY(bzero)
movl 12(%esp),%ecx
xorl %eax,%eax
shrl $2,%ecx
- cld
rep
stosl
movl 12(%esp),%ecx
@@ -90,7 +89,6 @@ ENTRY(i686_pagezero)
movl 12(%esp),%edi
movl $1024,%ecx
- cld
ALIGN_TEXT
1:
@@ -141,7 +139,6 @@ ENTRY(fillw)
movl 8(%esp),%eax
movl 12(%esp),%edi
movl 16(%esp),%ecx
- cld
rep
stosw
popl %edi
@@ -158,7 +155,6 @@ ENTRY(bcopyb)
subl %esi,%eax
cmpl %ecx,%eax /* overlapping && src < dst? */
jb 1f
- cld /* nope, copy forwards */
rep
movsb
popl %edi
@@ -199,7 +195,6 @@ ENTRY(bcopy)
jb 1f
shrl $2,%ecx /* copy by 32-bit words */
- cld /* nope, copy forwards */
rep
movsl
movl 16(%ebp),%ecx
@@ -245,7 +240,6 @@ ENTRY(memcpy)
movl 20(%esp),%ecx
movl %edi,%eax
shrl $2,%ecx /* copy by 32-bit words */
- cld /* nope, copy forwards */
rep
movsl
movl 20(%esp),%ecx
@@ -314,7 +308,6 @@ ENTRY(copyout)
movl %ebx,%ecx
shrl $2,%ecx
- cld
rep
movsl
movb %bl,%cl
@@ -365,7 +358,6 @@ ENTRY(copyin)
movb %cl,%al
shrl $2,%ecx /* copy longword-wise */
- cld
rep
movsl
movb %al,%cl
@@ -582,7 +574,6 @@ ENTRY(copyinstr)
movl %eax,20(%esp)
1:
incl %edx
- cld
2:
decl %edx
@@ -635,7 +626,6 @@ ENTRY(copystr)
movl 16(%esp),%edi /* %edi = to */
movl 20(%esp),%edx /* %edx = maxlen */
incl %edx
- cld
1:
decl %edx
jz 4f
@@ -675,7 +665,6 @@ ENTRY(bcmp)
movl %edx,%ecx
shrl $2,%ecx
- cld /* compare forwards */
repe
cmpsl
jne 1f
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