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Eliminate unneeded instructions that are a vestige of mechanical

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translation from i386.
This commit is contained in:
alc 2005-04-08 05:10:18 +00:00
parent 7e0854e7cd
commit 02ae1b51e3
1 changed files with 4 additions and 10 deletions
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14
lib/libc/amd64/string/bcopy.S
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@ -51,14 +51,14 @@ ENTRY(bcopy)
#endif
#endif
#if defined(MEMCOPY) || defined(MEMMOVE)
movq %rdi,%r11 /* save dest */
movq %rdi,%rax /* return dst */
#else
xchgq %rdi,%rsi
#endif
movq %rdx,%rcx
movq %rdi,%rax
subq %rsi,%rax
cmpq %rcx,%rax /* overlapping? */
movq %rdi,%r8
subq %rsi,%r8
cmpq %rcx,%r8 /* overlapping? */
jb 1f
cld /* nope, copy forwards. */
shrq $3,%rcx /* copy by words */
@ -68,9 +68,6 @@ ENTRY(bcopy)
andq $7,%rcx /* any bytes left? */
rep
movsb
#if defined(MEMCOPY) || defined(MEMMOVE)
movq %r11,%rax
#endif
ret
1:
addq %rcx,%rdi /* copy backwards. */
@ -87,8 +84,5 @@ ENTRY(bcopy)
subq $7,%rdi
rep
movsq
#if defined(MEMCOPY) || defined(MEMMOVE)
movq %r11,%rax
#endif
cld
ret