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/* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Pat Beirne <patb@corelcomputer.com>

   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.  */

#include <asm/errno.h>
#include <sys/syscall.h>

/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */

.text
.globl __clone;
.type __clone,%function
.align 4;
__clone:
        @ sanity check args
        cmp     r0, #0
        cmpne   r1, #0
        moveq   r0, #-EINVAL
        beq     __syscall_error (PLT)

        @ insert the args onto the new stack
        sub     r1, r1, #8
        str     r3, [r1, #4]
        @ save the function pointer as the 0th element
        str     r0, [r1]

        @ do the system call
        @ get flags
        mov     r0, r2
        @ new sp is already in r1
        swi     __NR_clone
        movs    a1, a1
        blt     __syscall_error  (PLT)
        movne    pc, lr

        @ pick the function arg and call address off the stack and execute
        ldr     r0, [sp, #4]
        mov     lr, pc
        ldr     pc, [sp]

        @ and we are done, passing the return value through r0
        b       _exit   (PLT)

__syscall_error:
        /* Looks like the syscall choked -- set errno */
        ldr  r3, .L4
        /* Calculate the - of the syscall result, in case we need it */
        rsb  r2, r0, $0

        /* errno = -result */
        str  r2, [r9,r3]

        /* return -1 */
        mvn  r0, $0
        mov  pc, lr
.size __clone,.-__clone;

.L4:  .word errno


.globl  clone;
    clone = __clone