RE: Library functions running in RAM

[Janáček Jiří <jiri dot janacek at skoda dot cz>]

-----Original Message-----
From: Janáček Jiří 
Sent: Monday, February 03, 2014 1:06 PM
To: 'gcc-help@gcc.gnu.org'
Subject: Library functions running in RAM

Dear all,

I am trying to produce the linker description file to allow the execution of some functions from RAM of Cortex-R4. These functions are compiled in a library.lib.
How should the linker description look to simply attach just needed functions from given library into the RAM section?

I have tried to apply a dirty way by enumerating the needed objects.
By using ar.exe I got a list of objects within included within the library. I need just a few functions contained in some of objects.

Nevertheless I received an error message that the regions FLASH0 and RAM_CODE overflowed by some Bytes (even KB) although there is enough space defined for these regions.

SECTIONS
{
    .text :
    {
      KEEP(*(.intvecs))
      *(.text*)
      *(EXCLUDE_FILE(a.obj b.obj))              
      *(.rodata*)
    } > FLASH0

    .ram_funcs :
    {
      ram_funcs_start = .;
      a.obj (*(.text*))
      b.obj (*(.text*))
    } > RAM_CODE AT > FLASH0
    ram_funcs_size = SIZEOF(.ram_funcs);
    ram_funcs_load_start = LOADADDR(.ram_funcs);

etc.

Of course, the program will perform copying the RAM functions from ROM during start-up.


Environment:
ARM Cortex-R4
GCC 4.8 2013q4


Kind regards

JiriJ

--------------------------------------

Dear all,

I have applied a few changes and re-ordered the sections:

SECTIONS
{
    .ram_funcs :
    {
      ram_funcs_start = .;
      *a.obj (.text*)
      *b.obj (.text*)
    } > RAM_CODE AT > FLASH0
    ram_funcs_size = SIZEOF(.ram_funcs);
    ram_funcs_load_start = LOADADDR(.ram_funcs);

    .text :
    {
      KEEP(*(.intvecs))
      *(EXCLUDE_FILE(a.obj b.obj), .text)              
      *(.text*)
      *(.rodata*)
    } > FLASH0

etc.


But the linker complains there are undefined references to the functions just defined in the objects a.obj and b.obj..
These object files are located in the known/defined path - the same one where other object files produced by the compiler are located.

Thanks for your hints in advance,
JiriJ