xref: /titanic_50/usr/src/lib/crt/i386/mach-crt1.s (revision f3e7f55e73a39377d55a030f124cc86b3b66a9cc)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26#include <sys/asm_linkage.h>
27
28	.file	"mach-crt1.s"
29
30/* global entities defined elsewhere but used here */
31	.globl	_start_crt
32
33/*
34 * C language startup routine.
35 * Assume that exec code has cleared the direction flag in the TSS.
36 * Assume that %esp is set to the addr after the last word pushed.
37 * The stack contains (in order): argc, argv[],envp[],...
38 * Assume that all of the segment registers are initialized.
39 *
40 * Allocate a NULL return address and a NULL previous %ebp as if
41 * there was a genuine call to _start.
42 * debugger stack trace shows _start(argc,argv[0],argv[1],...,envp[0],...)
43 */
44ENTRY_NP(_start)
45	pushl	$0
46	pushl	$0
47	movl	%esp,%ebp		/* The first stack frame */
48
49	/*
50	 * The stack needs to be 16-byte aligned with a 4-byte bias.  See
51	 * comment in lib/libc/i386/gen/makectxt.c.
52	 *
53	 * Note: If you change it, you need to change it in the following
54	 * files as well:
55	 *
56	 *  - lib/libc/i386/threads/machdep.c
57	 *  - lib/libc/i386/gen/makectxt.c
58	 *  - lib/crt/i386/crti.s
59	 */
60	andl	$-16,%esp	/* make main() and exit() be called with */
61	subl	$4,%esp		/* a properly aligned stack pointer */
62	pushl	%edx		/* possible atexit handler */
63	leal	12(%ebp),%edx	/* argv */
64	movl	8(%ebp),%eax	/* argc */
65	pushl	%edx
66	pushl	%eax
67	call	_start_crt
68	hlt
69SET_SIZE(_start)
70
71#include "fsr.s"
72
73/*
74 * The following is here in case any object module compiled with cc -p
75 * was linked into this module.
76 */
77ENTRY_NP(_mcount)
78	.weak	_mcount
79	ret
80SET_SIZE(_mcount)
81