1/*
2 * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.
29 *
30 *	File:	libc/ppc/sys/vfork.s
31 *
32 * HISTORY
33 * 23-Jun-1998	Umesh Vaishampayan (umeshv@apple.com)
34 *	Created from fork.s
35 *
36 */
37
38#include "SYS.h"
39
40#if defined(__i386__)
41
42#if defined(__DYNAMIC__)
43#define GET_CURRENT_PID	PICIFY(__current_pid)
44
45        NON_LAZY_STUB(__current_pid)
46#define __current_pid	(%edx)
47#else
48#define GET_CURRENT_PID
49#endif
50
51/*
52 * If __current_pid >= 0, we want to put a -1 in there
53 * otherwise we just decrement it
54 */
55
56LEAF(___vfork, 0)
57	GET_CURRENT_PID
58	movl		__current_pid, %eax
590:
60	xorl		%ecx, %ecx
61	testl		%eax, %eax
62	cmovs		%eax, %ecx
63	decl		%ecx
64	lock
65	cmpxchgl	%ecx, __current_pid
66	jne		0b
67	popl		%ecx
68	movl		$(SYS_vfork), %eax	// code for vfork -> eax
69	UNIX_SYSCALL_TRAP			// do the system call
70	jnb		L1                     	// jump if CF==0
71	GET_CURRENT_PID
72	lock
73	incl		__current_pid
74	pushl		%ecx
75	BRANCH_EXTERN(tramp_cerror)
76
77L1:
78	testl		%edx, %edx		// CF=OF=0,  ZF set if zero result
79	jz		L2			// parent, since r1 == 0 in parent, 1 in child
80	xorl		%eax, %eax		// zero eax
81	jmp		*%ecx
82
83L2:
84	GET_CURRENT_PID
85	lock
86	incl		__current_pid
87	jmp		*%ecx
88
89#elif defined(__x86_64__)
90
91/*
92 * If __current_pid >= 0, we want to put a -1 in there
93 * otherwise we just decrement it
94 */
95
96LEAF(___vfork, 0)
97	movq		__current_pid@GOTPCREL(%rip), %rax
98	movl		(%rax), %eax
990:
100	xorl		%ecx, %ecx
101	testl		%eax, %eax
102	cmovs		%eax, %ecx
103	subl		$1, %ecx
104	movq		__current_pid@GOTPCREL(%rip), %rdx
105	lock
106	cmpxchgl	%ecx, (%rdx)
107	jne		0b
108	popq		%rdi			// return address in %rdi
109	movq		$ SYSCALL_CONSTRUCT_UNIX(SYS_vfork), %rax	// code for vfork -> rax
110	UNIX_SYSCALL_TRAP			// do the system call
111	jnb		L1			// jump if CF==0
112	pushq		%rdi			// put return address back on stack for cerror
113	movq		__current_pid@GOTPCREL(%rip), %rcx
114	lock
115	addq		$1, (%rcx)
116	movq		%rax, %rdi
117	BRANCH_EXTERN(_cerror)
118
119L1:
120	testl		%edx, %edx		// CF=OF=0,  ZF set if zero result
121	jz		L2			// parent, since r1 == 0 in parent, 1 in child
122	xorq		%rax, %rax		// zero rax
123	jmp		*%rdi
124
125L2:
126	movq		__current_pid@GOTPCREL(%rip), %rdx
127	lock
128	addq		$1, (%rdx)
129	jmp		*%rdi
130
131#else
132#error Unsupported architecture
133#endif
134