xref: /freebsd/lib/csu/i386/crt1_s.S (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
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	.text
25	.align	4
26	.globl	_start
27	.type	_start, @function
28_start:
29	.cfi_startproc
30	.cfi_undefined %eip
31	popl	%esi		# Pop argc
32	.cfi_def_cfa_offset -4
33	movl	%esp,%edi	# argv starts at stack top
34	xorl	%ebp,%ebp
35	pushl	%ebp
36	.cfi_def_cfa_offset 0
37	movl	%esp,%ebp
38	.cfi_offset %ebp,-4
39	.cfi_def_cfa_register %ebp
40	andl	$0xfffffff0,%esp # align stack
41
42#ifdef GCRT
43	subl	$4,%esp		# Align stack for 7 arguments
44	pushl	$etext
45	pushl	$eprol
46eprol:
47#else
48	subl	$12,%esp	# Align stack for 5 arguments
49#endif /* GCRT */
50
51#ifdef PIC
52	calll	1f
531:	popl	%ebx
54	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b],%ebx
55	leal	main@GOTOFF(%ebx),%eax
56	pushl	%eax
57#else
58	pushl	$main
59#endif /* PIC */
60
61	pushl	%edx		# rtld cleanup
62	/* env = argv + argc + 1 */
63	movl	%edi,%eax	# env = argv
64	movl	%esi,%ecx
65	shll	$2,%ecx		# argc * 4
66	addl	%ecx,%eax	# env += argc
67	addl	$4,%eax		# env += 1
68	pushl	%eax		# env
69	pushl	%edi		# argv
70	pushl	%esi		# argc
71
72#ifdef GCRT
73	/*
74	 * __libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
75	 */
76	calll	__libc_start1_gcrt
77#else
78	/*
79	 * __libc_start1(argc, argv, env, cleanup, main);
80	 */
81#ifdef PIC
82	calll	__libc_start1@PLT
83#else
84	calll	__libc_start1
85#endif
86#endif /* GCRT */
87	int3
88	.cfi_endproc
89	.size	_start, . - _start
90
91	.section .note.GNU-stack,"",%progbits
92