sysdeps/unix/sysv/linux/m68k/clone.S

   1 /* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
   2    Contributed by Andreas Schwab (schwab@issan.informatik.uni-dortmund.de)
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /* clone is even more special than fork as it mucks with stacks
  20    and invokes a function in the right context after its all over.  */
  21
  22 #include <sysdep.h>
  23 #define _ERRNO_H        1
  24 #include <bits/errno.h>
  25
  26 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
  27
  28         .text
  29 ENTRY (__clone)
  30
  31         /* Sanity check arguments.  */
  32         movel   #-EINVAL, %d0
  33         movel   4(%sp), %a0             /* no NULL function pointers */
  34         tstl    %a0
  35         jeq     SYSCALL_ERROR_LABEL
  36         movel   8(%sp), %a1             /* no NULL stack pointers */
  37         tstl    %a1
  38         jeq     SYSCALL_ERROR_LABEL
  39
  40         /* Allocate space and copy the argument onto the new stack.  */
  41         movel   16(%sp), -(%a1)
  42
  43         /* Do the system call */
  44         exg     %d2, %a1                /* save %d2 and get stack pointer */
  45         movel   12(%sp), %d1            /* get flags */
  46         movel   #SYS_ify (clone), %d0
  47         trap    #0
  48         exg     %d2, %a1                /* restore %d2 */
  49
  50         tstl    %d0
  51         jmi     SYSCALL_ERROR_LABEL
  52         jeq     thread_start
  53
  54         rts
  55
  56 thread_start:
  57         subl    %fp, %fp        /* terminate the stack frame */
  58         jsr     (%a0)
  59         movel   %d0, -(%sp)
  60         jbsr    JUMPTARGET (_exit)
  61
  62 PSEUDO_END (__clone)
  63
  64 weak_alias (__clone, clone)