Re: [avr-gcc-list] When does the Stack Frame Pointer (Y) get setup?

[Georg-Johann Lay]

Bob Paddock wrote:
> When does the Stack Frame Pointer (Y) get setup?

- If a frame pointer is needed
- If its setup is not avoided, e.g. by attribute naked

> Should the following code work?

No.  The code obviously relies on a frame but inhibits frame
generation by "naked".

> I find it trashing memory in bss:
> 
> void id_filter_init8( void ) __attribute__ ((naked)) __attribute__
> ((section(".init8")));
> void id_filter_init8( void )
> {
>   uint8_t ff_u8[128U];
> 
>   /* memset() should really be used here */
>   for( uint16_t idx_u16 = 0U; idx_u16 < (uint16_t) sizeof( ff_u8 ); idx_u16++ 
> )
>     {
>       ff_u8[ idx_u16 ] = 0U;
>     }

Consider writing this as a constructor, i.e.
  __attribute__ ((constructor))
instead of
  __attribute__ ((naked, section(".init8")))

Johann