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/*
 * libc/sysdeps/linux/microblaze/vfork.S -- `vfork' syscall for linux/microblaze
 *
 *  Copyright (C) 2003  John Williams <jwilliams@itee.uq.edu.au>
 *  Copyright (C) 2001  NEC Corporation
 *  Copyright (C) 2001  Miles Bader <miles@gnu.org>
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License.  See the file COPYING.LIB in the main
 * directory of this archive for more details.
 * 
 * Written by Miles Bader <miles@gnu.org>
 * Microblaze port by John Williams
 */

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

#include <clinkage.h>

/* Clone the calling process, but without copying the whole address space.
   The calling process is suspended until the new process exits or is
   replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
   and the process ID of the new process to the old process.  */

.global C_SYMBOL_NAME(errno)

C_ENTRY (__vfork):
        addi    r12, r0, SYS_vfork
        bralid  r17, 0x08;
        nop
        addi    r4, r3, 125             // minimum err value
        blti    r4, 1f                  // is r3 < -125?
        rtsd    r15, 8                  // normal return
        nop
1:      sub     r3, r3, r0              // r3 = -r3
        swi     r3, r0, C_SYMBOL_NAME(errno);
        rtsd    r15, 8                  // error return
        nop
C_END(__vfork)

.weak   C_SYMBOL_NAME(vfork)
C_SYMBOL_NAME(vfork) = C_SYMBOL_NAME(__vfork)