glibc/sysdeps/x86_64/bsd-_setjmp.S

/* BSD `_setjmp' entry point to `sigsetjmp (..., 0)'.  x86-64 version.
   Copyright (C) 1994-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* This just does a tail-call to `__sigsetjmp (ARG, 0)'.
   We cannot do it in C because it must be a tail-call, so frame-unwinding
   in setjmp doesn't clobber the state restored by longjmp.  */

#include <sysdep.h>
#define _ASM
#define _SETJMP_H
#include <bits/setjmp.h>

ENTRY (_setjmp)
	/* Set up arguments, we only need to set the second arg.  */
	xorl %esi, %esi
#ifdef PIC
	jmp HIDDEN_JUMPTARGET (__sigsetjmp)
#else
	jmp __sigsetjmp
#endif
END (_setjmp)
libc_hidden_def (_setjmp)