Re: [avr-gcc-list] relocation truncated to fit: R_AVR_13_PCREL _asmfunc

[Mattias Svensson]

> Joerg Wunsch wrote:
>
> > > "relocation truncated to fit: R_AVR_13_PCREL _asmfunc"
> >
> > > It worked before when I was linking for at90s8535, now I am linking
> > > for atmega16.
> >
> > Sure.  On devices up to 8 KB of flash, an RJMP can reach the entire
> > flash address space.
> >
> >
> > > What exactly does avr-gcc mean with: "relocation truncated to fit: 
> > > R_AVR_13_PCREL _asmfunc"?
> >
> > The relocation for the jump target doesn't fit into the constraints
> > of the instruction (supposedly, 13 bits of relative target address).
> >
> >
> > > It obviously is something with the "rjmp" but what?
> >
> > Use JMP instead of RJMP.

I noted that the mega16 had JMP added to the instruction set, now I see 
why.

Just for the record, and my understanding.
rjmp is described as: PC <- PC + k +1
and jmp as: PC <- k
So on a at90s8535 and the like that does not have jmp the linker has to 
calculate k at every place the rjmp is used in a way that it relatively 
points to the absolute address of the function jumped to...
Am I on the right track here?


Mattias