1 /*******************************************************************************
2 Copyright (c) 2015, 2017 Walt Elam
5 Redistribution and use in source and binary forms, with or without
6 modification, are permitted provided that the following conditions are met:
8 1. Redistributions of source code must retain the above copyright notice,
9 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 3. Neither the name of the copyright holder nor the names of its
16 contributors may be used to endorse or promote products derived from
17 this software without specific prior written permission.
19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
23 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 POSSIBILITY OF SUCH DAMAGE.
30 *******************************************************************************/
31 /***************************************************************************//**
34 @brief Bootstrap code for compiling an ELF executable on an Intel cpu
35 *******************************************************************************/
37 .globl _start # Declare global _start symbol
40 pop %rdi # Place argc as first arg to main
41 mov %rsp, %rsi # Place location of argv[] as second arg to main
42 and $-16, %rsp # Realign stack on a 16-byte boundary
43 call main # Call main function
44 mov %rax, %rdi # Copy return value from main as argument to exit(2)
45 movq $60, %rax # Set rax to syscall number for exit
46 syscall # Execute the syscall specified in rax
