>    Good suggestion - I need to learn how to do this sort of thing (and
> anything for that matter) with scripts - another on my long list of todo
> projects.

As Olin and Isaac pointed out it is probably not a good idea if you plan to
replace the bootloader / or in this case the runtime library without
updating the application as well. Also it is easier to implement Isaac's
suggestion as there is no need for scripting. So I would say go for that one
:-)

Tamas



On Mon, Jan 19, 2009 at 4:54 PM, Tony Vandiver <tony@traceelectronics.com>w=
rote:

> Hi Tamas,
>
>    Good suggestion - I need to learn how to do this sort of thing (and
> anything for that matter) with scripts - another on my long list of todo
> projects.
>
> Thanks,
>
> Tony
>
>
> Tamas Rudnai wrote:
> >> You could put a 'jump table' at a fixed location in your bootstrap's
> >> program space, with each entry jumping to one routine that you may call
> >> from your application.
> >>
> >
> > Or you can use the MAP file to figure out the function entries and some
> > Perl/Python scripts to generate a similar function declaration as
> mentioned
> > by Isaac. You could then put that script into the tool path so that it
> will
> > run automatically every time you compile your application, so it will
> never
> > out of sync.
> >
> > Tamas
> >
> >
> > On Mon, Jan 19, 2009 at 10:57 AM, Isaac Marino Bavaresco <
> > isaacbavaresco@yahoo.com.br> wrote:
> >
> >
> >> Tony Vandiver escreveu:
> >>
> >>> I'm trying to write a custom bootstrap to load in my application code
> >>> from an SD card.  I want to call file I/O routines located in my
> >>> bootstrap from my application rather than duplicating the file I/O
> >>> library functions in the application because it represents about 10% =
of
> >>> my code space.  Typically when I compile, I compile and link everythi=
ng
> >>> that pertains to a project at the same time, but in this instance, do=
 I
> >>> need to reference an object file from the bootstrap compilation witho=
ut
> >>> compiling it into the application project, and if so, how do I keep it
> >>> from being relocated by the linker without expressly setting the
> address
> >>> of each function?  I'll start reading the compiler reference material
> >>> now and see how long it will take me to start drooling.
> >>>
> >>> Thanks for the help,
> >>>
> >>> Tony
> >>>
> >>>
> >> You could put a 'jump table' at a fixed location in your bootstrap's
> >> program space, with each entry jumping to one routine that you may call
> >> from your application.
> >>
> >> The reason for the 'jump table' is to make the entry points fixed, even
> >> if you change your bootstrap code.
> >>
> >> Assuming you are using MPLAB C18 (other Cs may have a slightly differe=
nt
> >> syntax, but not much even for other MCUs).
> >>
> >> In the bootstrap:
> >>
> >> #pragma code JUMPTABLE =3D 0x1f000
> >>
> >> void JumpTable( void )
> >>    {
> >>    _asm
> >>    goto mount;
> >>    goto remove;
> >>    goto ...
> >>    _endasm;
> >>    }
> >>
> >> #pragma code
> >>
> >> In your application you call the functions this way:
> >>
> >> typedef void (*func_type1)( void );   // Pointer to a function that ta=
ke
> >> void and return void;
> >> typedef int (*func_type2)( const char rom * );   // Pointer to a
> >> function that take a string and return int;
> >> ....
> >>
> >> #define mount() ((func_type1)0x1f000)() /* mount entry point is at
> >> 0x1f000 */
> >> #define remove(name) ((func_type2)0x1f004)(name) /* remove entry point
> >> is at 0x1f004 */
> >> ....
> >>
> >> void main( void )
> >>    {
> >>    mount();
> >>    remove( "backup.bin" );
> >>    }
> >>
> >> Best regards,
> >>
> >> Isaac
> >> __________________________________________________
> >> Fa=E7a liga=E7=F5es para outros computadores com o novo Yahoo! Messeng=
er
> >> http://br.beta.messenger.yahoo.com/
> >>
> >> --
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> >>
> >
> >
> >
> >
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