Re: [avr-gcc-list] Function Pointers on AT90USB1287 and ATmega2561

[Kasper Pedersen]

Weddington, Eric wrote:
>  
>   
> > But I do find it strange that the AT90USB1287 uses a 3 byte PC for
> > call/ret and reti, thought it only has 128K of flash.
> >     
>
> I find it extremely odd too, and I'm not at all sure that it is correct.
> Some investigation will have to be done to verify this information.
>   

unsigned char how_long_is_the_instruction_pointer(void)
{
 unsigned sp1=SP;  unsigned sp2; //store stack ptr
   asm volatile("call rrrtt\r\n rrrtt:\r\n"::);  //move stack ptr by 
calling
  sp2=SP; cli(); SP=sp1; sei(); //restore stack
 return sp1-sp2;
}

Result on USB1286 date code 0622 is 2
Result on USB1287 date code 0548 is also 2.

/Kasper Pedersen