Lpc2000

C syntax portion is easy:

void (*func)(void) = (void (*)())0x40000000;

(*func)();

At 04:17 PM 1/16/2005, sig5534 wrote:



> > 1) Try turning off the MAM to eliminate
> > this from the set of variable.
>
>Already using MAM_OFF.
>
> > 2) Are you using Thumb code? If so, perhaps the .data assignment is
> > throwing away the thumb attributes.
>
>Nope, 32b code.
>
> > 3) A Prefetch Abort means that there is no memory available at the
> > address you specify (like a data abort, but for instructions).
> >
> > The code
> >
> >     LDR  PC,[R5,#0]
> >
> > should be loading the pointer from this address
> > (ie. R5 + #0 should be a 32-bit value that is the pointer
> > to the code).
> >
> > Check that the address actually contains the **pointer**
> > to the code you want to execute and not the actual code itself.
>
>Now we're getting somewhere.  I think this is the problem.  I want it
>to jump to and execute at the 0x4000000 adr.  There is no pointer
>there.
>
> > Perhaps try
> >
> > static const (*fnptr)(void) = IAP_Test;
> >  ...
> >  *fnptr();
>
>That gives a compiler error:
>
>main.c:107: error: invalid type argument of `unary *'
>D:\GNUARM\bin\make: *** [main.o] Error 1
>
> > which should put the pointer in the literal pool and generate
> > different code.
>
>Yeh I think this is on the right track.  I need to get my C syntax
>correct here to generate a long jump directly rather than loading a
>pointer.  The function is at 0x40000000 not a pointer to it.
>
>If you have any other ideas for this, please pass them on.  Meanwhile
>I check my C books to try to figure out the needed syntax.
>
>Chris.
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>

// richard (This email is for mailing lists. To reach me directly, please 
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