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##=============================================================================

##

##      vectors.S

##

##      x86 exception vectors

##

##=============================================================================

#####ECOSGPLCOPYRIGHTBEGIN####

## -------------------------------------------

## This file is part of eCos, the Embedded Configurable Operating System.

## Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

##

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## 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

##

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## or inline functions from this file, or you compile this file and link it

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##=============================================================================

#######DESCRIPTIONBEGIN####

##

## Author(s):   bartv

## Contributors:bartv

## Date:        2001-03-16

## Purpose:     Synthetic target startup

## Description: When running on real hardware vectors.S contains

##              initialization code and usually the low-level interrupt and

##              exception support. On the synthetic target the latter is

##              handled by C code. The main initialization that is needed is

##              to jump into the C startup.

##

######DESCRIPTIONEND####

##

##=============================================================================

# According the SVR4/i386 ABI, most registers are undefined. However

# there is some interesting information on the stack:

#     %esp              argc

#     %esp+4            argv[0]

#     ...               argv[1 onwards]

#     %esp + (argc*4)   NULL

#     ...               environ[0]

#     ...               ...

#     ...               NULL

#

# There are some other things that could be done, for example aligning

# the stack to a 16-byte boundary for SSE, but it is not clear which of

# those things are actually useful. The glibc source file

# sysdeps/i386/elf/start.S contains some relevant information.

#==============================================================================

        .file   "vectors.S"

        .extern _linux_entry

        .data

        .global cyg_hal_sys_argc

cyg_hal_sys_argc:

        .long   0

        .global cyg_hal_sys_argv

cyg_hal_sys_argv:

        .long   0

        .global cyg_hal_sys_environ

cyg_hal_sys_environ:

        .long 0

        .text

        .globl  _start

_start:

        popl    %eax

        movl    %eax, cyg_hal_sys_argc

        movl    %esp, %ebx

        movl    %ebx, cyg_hal_sys_argv

        inc     %eax

        addl    %eax, %eax

        addl    %eax, %eax

        addl    %eax, %ebx

        movl    %ebx, cyg_hal_sys_environ

        jmp     _linux_entry