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#
# This file is part of the Free Pascal run time library.
# Copyright (c) 1999-2000 by Michael Van Canneyt and Peter Vreman
# 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
#
.file "prt1.as"
.text
.globl _start
.type _start,@function
_start:
/* First locate the start of the environment variables */
popl %esi
movl %esp,%ebx /* Points to the arguments */
movl %esi,%eax
incl %eax
shll $2,%eax
addl %esp,%eax
andl $0xfffffff0,%esp /* Align stack to 16 bytes */
movl %eax,operatingsystem_parameter_envp /* Move the environment pointer */
movl %esi,operatingsystem_parameter_argc /* Move the argument counter */
movl %ebx,operatingsystem_parameter_argv /* Move the argument pointer */
xorl %ebp,%ebp
pushl %edi /* __libc_start_main takes 7 arguments -> push 1 extra to keep 16 byte stack alignment */
pushl %esp
pushl %edx
pushl $_fini_dummy
pushl $_init_dummy
pushl %ebx
pushl %esi
pushl $main
call __libc_start_main
hlt
/* fake main routine which will be run from libc */
main:
/* save return address */
popl %eax
movl %eax,___fpc_ret
movl %ebx,___fpc_ret_ebx
movl %ebp,___fpc_ret_ebp
pushl %eax
/* Save initial stackpointer */
movl %esp,__stkptr
/* start the program */
xorl %ebp,%ebp
/* jmp to keep stack alignment */
jmp PASCALMAIN
.globl _haltproc
.type _haltproc,@function
_haltproc:
movzwl operatingsystem_result,%eax
movl ___fpc_ret,%edx /* return to libc */
movl ___fpc_ret_ebp,%ebp
movl ___fpc_ret_ebx,%ebx
push %edx
_init_dummy:
_fini_dummy:
ret
.data
.align 4
___fpc_ret: /* return address to libc */
.long 0
___fpc_ret_ebx:
.long 0
___fpc_ret_ebp:
.long 0
.bss
.type __stkptr,@object
.size __stkptr,4
.global __stkptr
__stkptr:
.skip 4
.type operatingsystem_parameters,@object
.size operatingsystem_parameters,12
operatingsystem_parameters:
.skip 3*4
.global operatingsystem_parameter_envp
.global operatingsystem_parameter_argc
.global operatingsystem_parameter_argv
.set operatingsystem_parameter_envp,operatingsystem_parameters+0
.set operatingsystem_parameter_argc,operatingsystem_parameters+4
.set operatingsystem_parameter_argv,operatingsystem_parameters+8
.section .note.GNU-stack,"",%progbits
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