NewLib start up code

[Sergio <hardmaker at gmail dot com>]

Hi,
I'm new working with newlib. I can build a complete toolchain to work
with ARM architecture and Cortex M3. I write my own crt0 and syscalls.
All work ... but when I do a call to any library function does not
work. Searching in the net read about a _init and _fini functions to
initialize the library. Now, my crt0 file have a invocation to this
functions after and before of main, like:

...
// initialize the stack
// initialize _bss

	_init();
    main();
	_fini();

...

When I this and link the application, recibe a error message from the
linker about override some segments. Searching about, find I must add
some declarations in then linker script to put the _init and _finit
code in the data segment. I use a linker script like this:


STARTUP(out/crt0.o)

ENTRY(main)

MEMORY
{

    FLASH (rx) : ORIGIN = 0x00000800, LENGTH = 0x1F7FF

    SRAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0xFFFF

}



SECTIONS

{

    .text :

    {

        _text = .;

        KEEP(*(.isr_vector))

        *(.text*)

        *(.rodata*)

        _etext = .;

      PROVIDE (_init = .);

      *crti.o(.init)

      *(.init)

      *crtn.o(.init)

      PROVIDE (_fini = .);

      *crti.o(.fini)

      *(.fini)

      *crtn.o(.fini)

		

    } > FLASH


    .data : AT(ADDR(.text) + SIZEOF(.text))

    {

        _data = .;

        *(vtable)

        *(.data*)

        _edata = .;

    } > SRAM

    .bss :

    {

	__bss_start = .;	

        *(.bss*)

        *(COMMON)

	__bss_end = .;

        . = ALIGN (8);

	_end = .;		

    } > SRAM

}



PROVIDE( _HEAP_START = _end );

PROVIDE ( _HEAP_END = ALIGN(ORIGIN(SRAM) + LENGTH(SRAM) - 8 ,8) );

This is correct? The application it's build fine, but die when run and
do a function library call. I must add some extra code to initialize
the internals of newlib? I need add some segment to the linker script
to do space to library data?

If anyone can help, of course thank you very much

Sergio