Re: [avr-gcc-list] Overlong interrupt vector table

[Richard F]

Thanks Eric,
I looked into it some more and it's a compiler "jump table" using "ijmp" 
- it looks like a continuation of the vector table - but it's actually 
been created out of a switch statement in my scheduler.  So doesn't look 
like any more optimisation to be had there!

Weddington, Eric wrote:
>  
>
> > -----Original Message-----
> > From: 
> > address@hidden 
> > [mailto:address@hidden
> > org] On Behalf Of Richard F
> > Sent: Tuesday, February 03, 2009 5:11 AM
> > To: address@hidden
> > Subject: [avr-gcc-list] Overlong interrupt vector table
> >
> > I'm working on a small application in an ATMEGA48p, and need 
> > a few extra bytes of code space.
> > This may have been answered before, but I can't find a reference...
> > Does anyone know why there are 40 vectors where Atmel specify 26 -
> > What are the last 14 items (that look like vectors) used for, 
> > and how can I make use of this "wasted space"?
> > (Is it a general purpose vector table for the largest possible AVR?)
> > Thx
>
> The vector table code is located in the startup code in avr-libc.
>
>  
> > <scheduler+0x26>
> >       36:    73 c2           rjmp    .+1254       ; 0x51e 
> > <scheduler+0x2a>
> >       38:    76 c2           rjmp    .+1260       ; 0x526 
> > <scheduler+0x32>
> >       3a:    7d c2           rjmp    .+1274       ; 0x536 
> > <scheduler+0x42>
> >       3c:    7f c2           rjmp    .+1278       ; 0x53c 
> > <scheduler+0x48>
> >       3e:    83 c2           rjmp    .+1286       ; 0x546 
> > <scheduler+0x52>
> >       40:    82 c2           rjmp    .+1284       ; 0x546 
> > <scheduler+0x52>
> >       42:    81 c2           rjmp    .+1282       ; 0x546 
> > <scheduler+0x52>
> >       44:    80 c2           rjmp    .+1280       ; 0x546 
> > <scheduler+0x52>
> >       46:    7f c2           rjmp    .+1278       ; 0x546 
> > <scheduler+0x52>
> >       48:    7e c2           rjmp    .+1276       ; 0x546 
> > <scheduler+0x52>
> >       4a:    7d c2           rjmp    .+1274       ; 0x546 
> > <scheduler+0x52>
> >       4c:    84 c2           rjmp    .+1288       ; 0x556 
> > <scheduler+0x62>
> >       4e:    83 c2           rjmp    .+1286       ; 0x556 
> > <scheduler+0x62>
>
> I have no idea where you are getting these <scheduler+xxxx> ids from. Perhaps 
> you're using an RTOS? But they certainly don't come from the startup code in avr-libc.