usr/src/lib/libc/i386/sys/Ovfork.s

/*-
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * %sccs.include.redist.c%
 */

#if defined(SYSLIBC_SCCS) && !defined(lint)
        .asciz "@(#)Ovfork.s    8.1 (Berkeley) %G%"
#endif /* SYSLIBC_SCCS and not lint */

#include "SYS.h"

/*
 * pid = vfork();
 *
 * %edx == 0 in parent process, %edx == 1 in child process.
 * %eax == pid of child in parent, %eax == pid of parent in child.
 *
 */
        .set    vfork,66
.globl  _vfork

_vfork:
        popl    %ecx            /* my rta into ecx */
        movl    $vfork, %eax
        LCALL(7,0)
        jb      verror
vforkok:
        cmpl    $0,%edx         /* child process? */
        jne     child           /* yes */
        jmp     parent
.globl  _errno
verror:
        movl    %eax,_errno
        movl    $-1,%eax
        jmp     %ecx
child:
        movl    $0,%eax
parent:
        jmp     %ecx