RE: [avr-gcc-list] Function pointers on > 128 KiB devices, how to?

[Stu Bell]

Cool idea, Dale!  I may give this a try in my code as it would make some
other problems simpler.

Best regards, 

Stu Bell 
DataPlay (DPHI, Inc.) 

 

> -----Original Message-----
> On Behalf Of Dale Whitfield
> Sent: Wednesday, January 20, 2010 8:54 AM
> 
> Hi Joerg                                         
> >@2010.01.20_15:53:55_+0200
> 
> This will create an explicit trampoline. The rest of your 
> code would remain the same. I've used this technique in a 
> slightly different way previously. Caution: Compiled and 
> inspected but not tested/simulated! 
> 
> #define JMP_TABLE_ENTRY(x)    __asm__ __volatile__ ("jmp "#x)
> 
> void jumptable_fn(void) __attribute__ ((naked)); void 
> jumptable_fn(void) {
>       JMP_TABLE_ENTRY(foo);
>       JMP_TABLE_ENTRY(bar);
>       JMP_TABLE_ENTRY(mumble);
> }
> 
> fptr jumptable[] __attribute__((progmem)) = {
>         jumptable_fn+0,       // foo
>         jumptable_fn+4,       // bar,
>         jumptable_fn+8,       // mumble,
> };
> 
> An advanced use for this is to allow creation of a 'jump 
> table' that can call functions that are not all of type fptr, 
> ie. void fn(void).
>