Re: [Sdcc-user] HELP NEEDED: error 25: Structure/Union expected left of '.->'

[N. A. C. <nes...@gm...>]

You put it very clear. The question now is if the PIC would at least
be able to represent a board and make some moves without committing
suicide. Maybe it could be used for some purpose: for example, to
control positions of the pieces on the board, and things like that,
then, a more powerful processor would be used for computations. But to
start, I would prefer a PIC, since it's easier to program than other,
more complex, solutions.

Thanks!! If any more comments, please, let me know!!

2008/8/14 Raphael Neider <rn...@we...>:
>> BTW, I have realized that I was compiling for the default target, not
>> PIC16. Now, I'm getting some linker errors. I'm attaching the sources,
>> you can test it just with
>> # make
>>
>> I have commented out "puts" and "#include <assert.h>" and two assertions.
>> But I still get the following:
>>
>> nestor@fijo-nestor:~/Desktop/chess/firstchess/pic16$ make
>> sdcc firstchess.c -mpic16 -o firstChess
>
> You are compiling for the default pic18f452, which may or not be what
> you want. Select the desired target chip with -mpic16 -p18f6720 (replace
> 6720 with your device code).
>
>> message: using default linker script "/usr/share/gputils/lkr/18f452.lkr"
>> warning: relocation of section "udata_firstchess_7" failed, relocating
>> to a shared memory location
>> error: linker script has no definition that matches the type of
>> section "udata_firstchess_7"
>> make: *** [all] Error 1
>>
>> Any idea?? Thanks!
>
> Yes: You are out of memory, and even if the device had enough memory,
> you fail to respect the data banking scheme of the PICs (BSR register).
>
> 1) You allocate the HIST hist[6000] array of 48000 bytes; the 18f452
> only has 6 banks of 256 bytes ==> 1536 bytes of memory.
>
> 2) The 18f6720 has 15 banks of 256 bytes of memory ==> 3840 bytes, which
> is all the PIC architecture can address (16 bank is split into access
> bank and SFRs and not available for general use).
>
> 3) Even if your array was the only data structure and was only 257 bytes
> in size, this error would occur still. The data memory is organized in
> banks of 256 bytes; no single object can be longer than that (has to do
> with BANKSEL directives and compiler internal assumptions about each
> structure/array residing completely in a single bank).
> In short, you must cut down the hist structure to (say) HIST hist[32],
> or modify the .lkr file to create a huge bank to accommodate *only* this
> array (you would have to make sure that other objects allocated to that
> superbank do not cross 256-byte boundaries, which you cannot do ==>
> problem in the linker rather than the compiler). Even then I cannot
> guarantee that the array access works as expected in all cases (it
> should, but such a setup is highly unusual and untested).
>
> Such problems caused my initial doubts on playing chess on a
> microcontroller. Knowing that you want to use PICs, I cannot see how to
> solve them: Other devices (8051-derivatives) have external memory, which
> might be useful in this case (if they can address 64 kB of memory), but
> with PICs I can only think of manually attached memory via 2 or more 8
> bit ports for addresses and data, SPI, ...
>
> Good luck,
> Raphael
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Sdcc-user mailing list
> Sdc...@li...
> https://lists.sourceforge.net/lists/listinfo/sdcc-user
>



-- 
Néstor
+34 687 96 74 81
nes...@gm...