Initializing Uninitialized data section (. bss) as zero in CCS 3.1

dixit parmar

Hi all,

I want to fill my. bss section with zero, I know one way by adding fill=0 syntax in cmd file but that is increasing size of hex file and that's not preferable for me.

I have heard another way that it can be done by making changes in boot. Asm file.

Can anyone guide me on this?

Thanks in advance

Dixit

over 9 years ago

0 Raja over 9 years ago

TI__Guru* 81335 points

Hi Dixit,

Please refer below thread for answer,

c55x: How to zero initialize .bss - Code Composer Studio forum - Code Composer Studio™︎ - TI E2E support...

e2e.ti.com

Zero-initializing .bss is a standard function of startup code, but unfortunately not for c55x. It can be done as follows. Your linker .cmd file has something

Thank you.

0 Singamsetty Vamsi over 9 years ago in reply to Raja

Intellectual 880 points

Hi Raja,

from Where i have to call this function?
would this method will initialize .bss before any global variable been used in main()function?
actually, i wanted the same effect as Fill=0 method.

Thanks fro the help,
Dixit

0 Archaeologist over 9 years ago in reply to Singamsetty Vamsi

TI__Guru* 84225 points

You can call it at the top of main, or you can modify the boot routine to call it once the stack is set up and it is legal to make function calls. Some targets have a hook in the boot routine for calls like this; what target are you using? What compiler version? (It is not the same as the CCS version.)

0 dixit parmar over 9 years ago in reply to Archaeologist

Prodigy 200 points

Hello sir,

I am working with C55x. on CCS3.1.

Thanks,

Dixit

0 Archaeologist over 9 years ago in reply to dixit parmar

TI__Guru* 84225 points

Okay, C55x does not have those hooks in the default _c_int00 routine in the RTS. Copy boot.asm (found in lib/rtssrc.zip) into your project and modify it as follows:

        .ref _zero_bss
        call _zero_bss
        call _auto_init
        call __args_main

And add this function somewhere in your C code:

#include <string.h>
extern unsigned char *__bss__, *__end__;
void zero_bss(void)
{
    memset(__bss__, 0, __end__ -  __bss__); 
}