xref: /freebsd/lib/csu/i386/crt1_s.S (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
1/*-
2 * Copyright 2009 Konstantin Belousov.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *
11 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
12 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
13 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
14 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
15 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
16 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
17 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
18 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
19 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
20 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
21 */
22
23#include <machine/asm.h>
24__FBSDID("$FreeBSD$");
25
26	.text
27	.align	4
28	.globl	_start
29	.type	_start, @function
30_start:
31	.cfi_startproc
32	.cfi_undefined %eip
33	popl	%esi		# Pop argc
34	.cfi_def_cfa_offset -4
35	movl	%esp,%edi	# argv starts at stack top
36	xorl	%ebp,%ebp
37	pushl	%ebp
38	.cfi_def_cfa_offset 0
39	movl	%esp,%ebp
40	.cfi_offset %ebp,-4
41	.cfi_def_cfa_register %ebp
42	andl	$0xfffffff0,%esp # align stack
43
44#ifdef GCRT
45	subl	$4,%esp		# Align stack for 7 arguments
46	pushl	$etext
47	pushl	$eprol
48eprol:
49#else
50	subl	$12,%esp	# Align stack for 5 arguments
51#endif /* GCRT */
52
53#ifdef PIC
54	calll	1f
551:	popl	%ebx
56	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b],%ebx
57	leal	main@GOTOFF(%ebx),%eax
58	pushl	%eax
59#else
60	pushl	$main
61#endif /* PIC */
62
63	pushl	%edx		# rtld cleanup
64	/* env = argv + argc + 1 */
65	movl	%edi,%eax	# env = argv
66	movl	%esi,%ecx
67	shll	$2,%ecx		# argc * 4
68	addl	%ecx,%eax	# env += argc
69	addl	$4,%eax		# env += 1
70	pushl	%eax		# env
71	pushl	%edi		# argv
72	pushl	%esi		# argc
73
74#ifdef GCRT
75	/*
76	 * __libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
77	 */
78	calll	__libc_start1_gcrt
79#else
80	/*
81	 * __libc_start1(argc, argv, env, cleanup, main);
82	 */
83#ifdef PIC
84	calll	__libc_start1@PLT
85#else
86	calll	__libc_start1
87#endif
88#endif /* GCRT */
89	int3
90	.cfi_endproc
91	.size	_start, . - _start
92
93	.section .note.GNU-stack,"",%progbits
94