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{
This file is part of the Free Pascal run time library.
Copyright (c) 2005 by Michael Van Canneyt, Peter Vreman,
& Daniel Mantione, members of the Free Pascal development team.
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program 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.
**********************************************************************}
{
Linux ELF startup code for Free Pascal
Stack layout at program start:
nil
envn
....
.... ENVIRONMENT VARIABLES
env1
env0
nil
argn
....
.... COMMAND LINE OPTIONS
arg1
arg0
argc <--- esp
}
{$asmmode att}
var
dlexitproc: pointer; { atexit from loader }
procedure libc_start_main; external name '__libc_start_main';
procedure PASCALMAIN; external name 'PASCALMAIN';
{ Some helpers }
procedure _init_fini_dummy; compilerproc; nostackframe; assembler;
asm
ret
end;
{******************************************************************************
glibc 2.1 lib + profiling start/halt
******************************************************************************}
procedure _FPC_libc21_start; assembler; nostackframe; public name '_start';
asm
xorl %ebp,%ebp
{ First locate the start of the environment variables }
popl %ecx { Get argc in ecx }
movl %esp,%ebx { Esp now points to the arguments }
leal 4(%esp,%ecx,4),%eax { The start of the environment is: esp+4*eax+4 }
andl $0xfffffff8,%esp { Align stack }
{$ifdef FPC_PIC}
pushl %edx
pushl %ebx
pushl %ecx
call .Lpiclab
.Lpiclab:
popl %ebx
addl $_GLOBAL_OFFSET_TABLE_+1,%ebx
movl dlexitproc@GOT(%ebx),%ecx
movl %edx,(%ecx)
movl operatingsystem_parameter_envp@GOT(%ebx),%ecx
movl %eax,(%ecx)
movl operatingsystem_parameter_argc@GOT(%ebx),%edx
popl %ecx
movl %ecx,(%edx)
movl operatingsystem_parameter_argv@GOT(%ebx),%edx
popl %ebx
movl %ebx,(%edx)
popl %edx
{$else FPC_PIC}
movl %edx, dlexitproc
movl %eax,operatingsystem_parameter_envp
movl %ecx,operatingsystem_parameter_argc
movl %ebx,operatingsystem_parameter_argv
{$endif FPC_PIC}
{ Save initial stackpointer }
{$ifdef FPC_PIC}
pushl %ebx
call .Lpiclab2
.Lpiclab2:
popl %ebx
addl $_GLOBAL_OFFSET_TABLE_+1,%ebx
movl initialstkptr@GOT(%ebx),%ebx
movl %esp,(%ebx)
popl %ebx
{$else FPC_PIC}
movl %esp,initialstkptr
{$endif FPC_PIC}
{ int __libc_start_main(
int *(main) (int, char * *, char * *),
int argc,
char * * ubp_av,
void (*init) (void),
void (*fini) (void),
void (*rtld_fini) (void),
void (* stack_end)); }
pushl %ebp { padding }
pushl %esp { stack_end }
pushl %edx { function to be registered with
atexit(), passed by loader }
pushl $_init_fini_dummy
pushl $_init_fini_dummy
pushl %ebx { Push second argument: argv. }
pushl %ecx { Push first argument: argc. }
pushl $PASCALMAIN
call libc_start_main
hlt
end;
procedure _FPC_libc21_haltproc; assembler; nostackframe; public name '_haltproc';
asm
.Lhaltproc:
{$ifdef FPC_PIC}
call .Lpiclab
.Lpiclab:
popl %ebx
addl $_GLOBAL_OFFSET_TABLE_+1,%ebx
movl dlexitproc@GOT(%ebx),%eax
movl (%eax),%eax
{$else FPC_PIC}
movl dlexitproc,%eax
{$endif FPC_PIC}
testl %eax,%eax
je .Lnodlexitproc
call *%eax
.Lnodlexitproc:
movl syscall_nr_exit_group,%eax
{$ifdef FPC_PIC}
call .Lpiclab2
.Lpiclab2:
popl %ebx
addl $_GLOBAL_OFFSET_TABLE_+1,%ebx
movl ExitCode@GOT(%ebx),%ebx
{$if sizeof(ExitCode)=2}
movzwl (%ebx),%ebx
{$else}
mov (%ebx),%ebx
{$endif}
{$else FPC_PIC}
{$if sizeof(ExitCode)=2}
movzwl ExitCode,%ebx
{$else}
mov ExitCode,%ebx
{$endif}
{$endif FPC_PIC}
int $0x80
movl syscall_nr_exit,%eax
{$ifdef FPC_PIC}
call .Lpiclab3
.Lpiclab3:
popl %ebx
addl $_GLOBAL_OFFSET_TABLE_+1,%ebx
movl ExitCode@GOT(%ebx),%ebx
{$if sizeof(ExitCode)=2}
movzwl (%ebx),%ebx
{$else}
mov (%ebx),%ebx
{$endif}
{$else FPC_PIC}
{$if sizeof(ExitCode)=2}
movzwl ExitCode,%ebx
{$else}
mov ExitCode,%ebx
{$endif}
{$endif FPC_PIC}
int $0x80
jmp .Lhaltproc
end;
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