vfork.s

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

/* Copyright (C) 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Jakub Jelinek <[e-mail]>, 1999.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

/* Code taken from glibc2.2.2/sysdeps/unix/sysv/linux/sparc/vfork.S */

#include <sys/syscall.h>

#ifndef __NR_vfork
/* uClinux-2.0 only has fork which is really vfork */
#define __NR_vfork __NR_fork
#endif

.text;  
.global	vfork;
.align 4;
.type	vfork,@function;

vfork:
	mov __NR_vfork, %g1
	ta	0x10
	bcc,a	9000f
	nop
	save    %sp,-96,%sp
	call __errno_location
	nop
	st	%i0,[%o0]
	jmpl	%i7+8,%g0
	restore	%g0,-1,%o0

9000:
	sub	%o1, 1, %o1
	retl
	and	%o0, %o1, %o0

.size vfork,.-vfork;