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patch by njk, simplifies thread register initialization for x86_64

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It's not necessary to save any registers on the stack across syscall in
x86_64 __set_thread_area.  Don't waste cycles or bytes on it.
This commit is contained in:
Rich Felker 2011-02-16 09:50:57 -05:00
commit e3657ba599
1 changed files with 0 additions and 4 deletions
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4
src/thread/x86_64/__set_thread_area.s
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@ -3,13 +3,9 @@
.global __set_thread_area .global __set_thread_area
.type __set_thread_area,%function .type __set_thread_area,%function
__set_thread_area: __set_thread_area:
push %rbx /* save x86_64 abi clobbered registers */
push %r11
mov %rdi,%rsi /* shift for syscall */ mov %rdi,%rsi /* shift for syscall */
movl $0x1002,%edi /* SET_FS register */ movl $0x1002,%edi /* SET_FS register */
movl $158,%eax /* set fs segment to */ movl $158,%eax /* set fs segment to */
syscall /* arch_prctl(SET_FS, arg)*/ syscall /* arch_prctl(SET_FS, arg)*/
pop %r11 /* restore clobbered registers */
pop %rbx
ret ret
.size __set_thread_area,.-__set_thread_area .size __set_thread_area,.-__set_thread_area