2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright (C) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 #include <machine/asm.h>
35 * The program entry point
37 * void _start(char **ap, void (*cleanup)(void)) __dead2
40 .type _start, @function
43 .cfi_undefined %rip /* Terminate call chain. */
44 pushq %rbp /* Align stack, terminate call chain. */
48 .cfi_def_cfa_register %rbp
53 movq %rdi, %rsi /* argv = ap */
54 addq $8, %rsi /* argv += 1 */
55 movq %rdi, %rdx /* env = ap */
56 addq $16, %rdx /* env += 2 */
58 movl %eax, %edi /* argc = *(long *)(void *)ap */
60 addq %rax, %rdx /* env += argc */
63 * XXX. %rip relative addressing is not intended for use in the
64 * large memory model due to the offset from %rip being limited
67 leaq main@plt(%rip), %r8
76 * %edi %rsi %rdx %rcx %r8 %r9 (%rsp)
77 * __libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext)
79 callq __libc_start1_gcrt
82 /* __libc_start1(argc, argv, env, cleanup, main) */
87 .size _start, . - _start
89 .section .note.GNU-stack,"",%progbits