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sortix--sortix/libc/x64/crt0.S
Jonas 'Sortie' Termansen 6b4dbe0358 Rename crt1.o to crt0.o and install compatibility crt1.o.
This prepares for an incompatible compiler toolchain change scheduled for
Sortix 0.10 development where crt0.o is used instead of crt1.o.
2014-11-21 00:03:29 +01:00

57 lines
1.7 KiB
ArmAsm

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
This file is part of the Sortix C Library.
The Sortix C Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
The Sortix C Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
x64/crt0.S
Implement the _start symbol at which execution begins which performs the
task of initializing the standard library and executing the main function.
*******************************************************************************/
.section .text
.global _start
.type _start, @function
_start:
# Set up end of the stack frame linked list.
xorl %ebp, %ebp
pushq %rbp # rip=0
pushq %rbp # rbp=0
movq %rsp, %rbp
movq %rcx, environ # envp
# Prepare signals, memory allocation, stdio and such.
pushq %rsi
pushq %rdi
pushq %rcx
call initialize_standard_library
# Run the global constructors.
call _init
# Run main
popq %rdx # Note! envp is now %rdx (previously %rcx)
popq %rdi
popq %rsi
call main
# Terminate the process with main's exit code.
movl %eax, %edi
call exit
.size _start, .-_start