Re: [avr-gcc-list] Pointer to a function in a structure in flash?

[E . Weddington]

> 
> 
> On Tue, 28 Oct 2003, Bob Paddock wrote:
> 
> > On Mon, 27 Oct 2003 22:20:30 GMT, E.Weddington 
<address@hidden> wrote:
> >
> > >>  #if defined( __GCC_VERSION__ )
> > >>     retval =
> > >>     (*((functype_t)(pgm_read_word(&cmd_func_table
[i].function))))(
> > >>         (char const *)token,
> > >>         (char const *)tokptr);
> > >>  #endif
> 
> [snip]
> 
> > I tried that and the system goes off to never-never-
land, what I have
> > above works, below does not (I did change [0] to [i] as 
required).
> >
> > > #if defined( __GCC_VERSION__ )
> > > retval = cmd_func_table[0].function((CONST char *) 
token,
> > > (CONST char *) tokptr);
> > > #endif
> 
> I don't think this second version is ever reading the 
function pointer
> from program space which is why is goes to never-never-
land.  It
> should probably look something like this:
> 
> #if defined( __GCC_VERSION__ )
>   functype_t func = (functype_t)pgm_read_word
(&cmd_func_table[i].function);
>   retval = func ((CONST char *) token, (CONST char *) 
tokptr);
> #endif
> 
> The code that Eric posted yesterday had the same problem. 
If you look
> at the assembly listing, there was no LPM insn to pull 
the function
> from program space.
> 
> Ted Roth
> 

D'oh! Thanks for catching that Ted. Mea culpa.

Eric