[ARM cortex-m0] sync built-in functions for atomic memory access

[Mallikarjun Goudar <mallikarjun.gouda@xxxxxxxxx>]

Hi,
I would like to use sync built-in functions for atomic memory access
fro the target arm cortex-m0.
But i do get error when i use them.

For example:
int main(void)
{
   int x = 2;
   __sync_add_and_fetch(&x, 1);

    return x;
}


I get following error:
undefined reference to `__sync_add_and_fetch_4'

I used following command:
arm-none-eabi-gcc -mcpu=cortex-m0 -mthumb -mfloat-abi=soft -c test.c

Thanks for your help,
Mallikarjuna