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

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

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

#define a0  $16
#define a1  $17
#define a2  $18
#define a3  $19
#define v0  $0
#define fp  $15
#define gp  $29
#define ra  $26
#define pv  $27
#define zero  $31

        .text
.globl  __clone;
.align 3;
.ent  __clone , 0;

__clone:
        .frame $30 , 0, $26
#ifdef PROF
        ldgp    gp,0(pv)
        .set noat
        lda     AT, _mcount
        jsr     AT, (AT), _mcount
        .set at
        .prologue 1
#else
        .prologue 0
#endif

        /* Sanity check arguments.  */
        ldiq    v0,EINVAL
        beq     a0,$error               /* no NULL function pointers */
        beq     a1,$error               /* no NULL stack pointers */

        /* Save the fn ptr and arg on the new stack.  */
        subq    a1,16,a1
        stq     a0,0(a1)
        stq     a3,8(a1)

        /* Do the system call */
        mov     a2,a0
        ldiq    v0,__NR_clone
        call_pal 131

        bne     a3,$error
        beq     v0,thread_start

        /* Successful return from the parent */
        ret

        /* Something bad happened -- no child created */
$error:
#ifndef PROF
        br      gp,1f
1:      ldgp    gp,0(gp)
#endif
        jmp     zero,__syscall_error

.end __clone

/* Load up the arguments to the function.  Put this block of code in
   its own function so that we can terminate the stack trace with our
   debug info.  */

        .ent thread_start
thread_start:
        .frame fp,0,zero,0
        mov     zero,fp
        .prologue 0

        /* Load up the arguments.  */
        ldq     pv,0($30)
        ldq     a0,8($30)
        addq    $30,16,$30

        /* Call the user's function */
        jsr     ra,(pv)
        ldgp    gp,0(ra)

        /* Call _exit rather than doing it inline for breakpoint purposes */
        mov     v0,a0
        jsr     ra,_exit

        /* Die horribly.  */
        halt

        .end thread_start

.weak    clone;
    clone    =   __clone