From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 16 Feb 2011 14:50:57 +0000 (-0500)
Subject: patch by njk, simplifies thread register initialization for x86_64
X-Git-Tag: v0.6.0~14
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=e3657ba5992468f0340efdb741ec32ac0e0acb5c;p=oweals%2Fmusl.git

patch by njk, simplifies thread register initialization for x86_64

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.
---

diff --git a/src/thread/x86_64/__set_thread_area.s b/src/thread/x86_64/__set_thread_area.s
index ed35b7a8..faf73ec4 100644
--- a/src/thread/x86_64/__set_thread_area.s
+++ b/src/thread/x86_64/__set_thread_area.s
@@ -3,13 +3,9 @@
 .global __set_thread_area
 .type   __set_thread_area,%function
 __set_thread_area:
-        push %rbx               /* save x86_64 abi clobbered registers */
-        push %r11
         mov %rdi,%rsi           /* shift for syscall */
         movl $0x1002,%edi       /* SET_FS register */
         movl $158,%eax          /* set fs segment to */
         syscall                 /* arch_prctl(SET_FS, arg)*/
-        pop %r11                /* restore clobbered registers */
-        pop %rbx
 	ret
 .size __set_thread_area,.-__set_thread_area