Objcopy pads 0s up to my new section

Euler M. OP #1173865 
Nice day Everyone!

Working with a CLPS7312, I try to use the on chip ram for some
variables. Program runs from external ram, mapped to 0x00000000. Up to
now, all uninited variables were in bss located after .text and .data in
external ram. Objcopy made the binary image, not including .bss. After
introducing .ocram in the ld script file and specifying WORD8
Buffer[BSIZE]__attribute__ ((section (".ocram"))) ; the resulting binary
file is bigger, including the space up to ocram filled with 0s. Ocram is
mapped to 0xb00000.
Could you please tell me, what do I need to modify not to fill the image
with zeros?

I use the followings:
in Makefile:
mass: $(USBECG_SRC) mainecg_mass.c Makefile
//MappedSRamBase=0x0
  $(XCC) $(XCFLAGS) $(INCLUDE_S) $(DEFINES_MASS) \
    -Wl,-Ttext,$(MappedSRamBase) -Wl,--section-start,ocram=0xb04000 -o
usbecg_v$(VERSION_MASS)_mass.elf $(USBECG_SRC) mainecg_mass.c 2>err
  $(XOBJDUMP) usbecg_v$(VERSION_MASS)_mass.elf | hex >
usbecg_v$(VERSION_MASS)_mass.lst
  $(XOBJCOPY) -O binary usbecg_v$(VERSION_MASS)_mass.elf
../bin/usbecg_v$(VERSION_MASS)_mass.bin

in the scriptfile:

OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
OUTPUT_ARCH(arm)
ENTRY(_start)

SECTIONS
{
  /* first section is .text which is used for code */
/*  . = 0x0000000;*/

  .text : { *cstartup.o (.text) }
  .text :
  {
    *(.text)                   /* remaining code */

    *(.glue_7t) *(.glue_7)
  }
  . = ALIGN(4);
  /* .rodata section which is used for read-only data (constants) */
  .rodata :
  {
    *(.rodata)
  }
  . = ALIGN(4);
  _etext = . ;
  PROVIDE (etext = .);
  /* .data section which is used for initialized data */
  .data : AT (_etext)
  {
    _data = . ;
  *(.fastrun)
  . = ALIGN(4);
    *(.data)
    SORT(CONSTRUCTORS)
  . = ALIGN(4);
  }
  . = ALIGN(4);
  _edata = . ;
   PROVIDE (edata = .);
  /* .bss section which is used for uninitialized data */
  .bss :
  {
    __bss_start = . ;
    _bss_start_ = . ;
    *(.bss)
    *(COMMON)
  }
  . = ALIGN(4);
  _bss_end_ = . ;
  _bss_end_ = . ;
  _end = .;

  .ocram  :
  {
    *(.ocram) ;
  }
  . = ALIGN(4);

    . = ALIGN(4);
   .int_data :
   {
   *(.internal_ram_top)
   }
  PROVIDE (end = .);
}

Thank you!
Megyer
Reply Quote Edit Move Thread sperren Slow mode Anmeldepflicht aktivieren Anpinnen Delete topic Thread mit anderem zusammenführen Report Thanks
Clifford S. #1173867 
Euler Megyer wrote:
> Could you please tell me, what do I need to modify not to fill the image
> with zeros?

Read the documentation perhaps:

arm-elf-objcopy --help

You will see the option: --gap-fill <val>

Clifford
Reply Quote Edit Delete Report Thanks
Clifford S. #1173868 
Clifford Slocombe wrote:
>
> You will see the option: --gap-fill <val>
>
Oh, sorry; I see what you mean, it wasn't teh zeros that concern you,
but rather the padding.

A binary image has no way of marking section locations since it is a
flat image of your application, and has no location or addressing
information. The various hex formats have location information, so you
might use those.

An alternative is to run objcopy twice once with --only-section ocram
and again with --remove-section ocram. You will then get two images that
you have to program separately to the required location. This seems
rather error prone to me.
Reply Quote Edit Delete Report Thanks
Euler M. OP #1173869 
Clifford Slocombe wrote:

> An alternative is to run objcopy twice once with --only-section ocram
> and again with --remove-section ocram. You will then get two images that
> you have to program separately to the required location. This seems
> rather error prone to me.

Thanks, --remove-section .ocram gives the result I need (you need the
dot before ocram!)

> A binary image has no way of marking section locations since it is a
> flat image of your application, and has no location or addressing
> information. The various hex formats have location information, so you
> might use those.

I was wondering if there is a way to treat the ocram section just like
bss, since neither have initialized variables and the bin file does not
contain bss filled with 0s when ocram is not used.

I use the package WinARM20060606.
Reply Quote Edit Delete Report Thanks
Watch this topic

Reply

A question of your own? This thread is over 18 years old. Ask it in a thread of its own – more people read along there, and it gets answered more often and sooner.

Start a new thread

A fix, an addition or feedback on this thread? Then reply here.

Formatting
  • [c]C-Code[/c]
  • [code]code in other languages, ASCII drawings[/code]
  • [math]formula (LaTeX syntax)[/math]
  • [[Title]] – link to an article
  • Link to another post: right-click its post ID (#8078628), copy the address, paste it into the text

More about formatting

Post long source code as an attachment, not in the text.

Your name and e-mail address

Already registered? Log in

Not shown to anyone. We send you a link; your post appears once you confirm it there.

By submitting you create a free account and accept the terms of use.