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/* Copyright (C) 1996 Free Software Foundation, Inc.
   Contributed by Andreas Schwab (schwab@issan.informatik.uni-dortmund.de)

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

/* clone is even more special than fork as it mucks with stacks
   and invokes a function in the right context after its all over.  */

#include <sysdep.h>
#include <errnos.h>

/* int clone (int (*fn) (), void *child_stack, int flags, int nargs, ...) */

        .text
ENTRY (__clone)
	/* Sanity check arguments.  */
	movel	#-EINVAL, %d0
	movel	4(%sp), %a0		/* no NULL function pointers */
	tstl	%a0
	jeq	syscall_error
	movel	8(%sp), %a1		/* no NULL stack pointers */
	tstl	%a1
	jeq	syscall_error
	movel	16(%sp), %d1		/* no negative argument counts */
	jmi	syscall_error

	/* Allocate space on the new stack and copy args over */
	movel	%d1, %d0
	negl	%d0
	lea	(%a1,%d0.l*4), %a1
	jeq	2f
1:	movel	16(%sp,%d1.l*4), -4(%a1,%d1.l*4)
	subql	#1, %d1
	jne	1b
2:

	/* Do the system call */
	exg	%d2, %a1		/* save %d2 and get stack pointer */
	movel	12(%sp), %d1		/* get flags */
	movel	#SYS_ify (clone), %d0
	trap	#0
	exg	%d2, %a1		/* restore %d2 */

	tstl	%d0
	jmi	syscall_error
	jeq	thread_start

	rts

	SYSCALL_ERROR_HANDLER

thread_start:
	subl	%fp, %fp	/* terminate the stack frame */
	jsr	(%a0)
	movel	%d0, -(%sp)
#ifdef PIC
	bsrl	_exit@PLTPC
#else
	jbsr	_exit
#endif

weak_alias (__clone, clone)