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/* Copyright (C) 1996,1997,98,99,2000,02,03 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Richard Henderson (rth@tamu.edu)

   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.  */

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

   Hacked up for uClibc by Erik Andersen <andersen@codepoet.org>
*/

#define _ERRNO_H        1
#include <features.h>
#include <bits/errno.h>

/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
             pid_t *ptid, struct user_desc *tls, pid_t *ctid); */

#define LINKAGE     4
#define PTR_SIZE    4
#define PARMS       LINKAGE        /* no space for saved regs */
#define FUNC        PARMS
#define STACK       FUNC+4
#define FLAGS       STACK+PTR_SIZE
#define ARG         FLAGS+4
#define PTID        ARG+PTR_SIZE
#define TLS         PTID+PTR_SIZE
#define CTID        TLS+PTR_SIZE

#define __NR_clone        120
#define __NR_exit         1

.text
.type clone,@function;
.weak clone ; clone = __clone

.type __clone,@function;
.globl __clone;

__clone:
        /* Sanity check arguments.  */
        movl    $-EINVAL,%eax

        /* no NULL function pointers */
        movl    FUNC(%esp),%ecx
        jecxz   .Lclone_error

        /* no NULL stack pointers */
        movl    STACK(%esp),%ecx
        jecxz   .Lclone_error

        /* Insert the argument onto the new stack.  Make sure the new
           thread is started with an alignment of (mod 16).  */
        andl    $0xfffffff0, %ecx
        subl    $24,%ecx
        movl    ARG(%esp),%eax          /* no negative argument counts */
        movl    %eax,12(%ecx)

        /* Save the function pointer as the zeroth argument.
           It will be popped off in the child in the ebx frobbing below.  */
        movl    FUNC(%esp),%eax
        movl    %eax,8(%ecx)
        /* Don't leak any information.  */
        movl    $0,4(%ecx)
        movl    $0,(%ecx)

        /* Do the system call */
        pushl   %ebx
        pushl   %esi
        pushl   %edi
        movl    TLS+12(%esp),%esi
        movl    PTID+12(%esp),%edx
        movl    FLAGS+12(%esp),%ebx
        movl    CTID+12(%esp),%edi
        movl    $__NR_clone,%eax
        int     $0x80
        popl    %edi
        popl    %esi
        popl    %ebx

        test    %eax,%eax
        jl      .Lclone_error
        jz      .Lthread_start

.Lpseudo_end:
        ret

.Lthread_start:
        subl    %ebp,%ebp       /* terminate the stack frame */
        call    *%ebx
#ifdef __PIC__
        call    .Lhere
.Lhere:
        popl    %ebx
        addl    $_GLOBAL_OFFSET_TABLE_+[.-.Lhere], %ebx
#endif
        movl    %eax, %ebx
        movl    $__NR_exit, %eax
        int     $0x80

#ifdef __PIC__

.Lthere:
        movl    (%esp), %ebx
        ret

.Lclone_error:
        pushl %ebx
        call .Lthere
        addl $_GLOBAL_OFFSET_TABLE_, %ebx
        xorl %edx, %edx
        subl %eax, %edx
        pushl %edx
        call __errno_location@PLT
        popl %ecx
        popl %ebx
        movl %ecx, (%eax)
        orl $-1, %eax
        jmp .Lpseudo_end

#else   /* __PIC__ */

.Lclone_error:
        negl    %eax
        pushl   %eax
        call    __errno_location
        popl    %ecx
        movl    %ecx, (%eax)
        xorl    %eax, %eax
        decl    %eax

#endif

.size __clone,.-__clone