[Icc-avr] Bootloader

[Johan Wallström]

Hi

I can think of two solutions: 
1. Define addresses where the functions are located. Call these functions using pointers to functions.
2. To allow the functions to be at any address, have a table located at a specified address (in the bootloader area) containg the addresses of the functions you want to call.

Here's an example of a function pointer (from a project in another compiler though):
int (*ReadIgnition)(ubyte &ignitionStatus);

So it's just called something like this:
ubyte resultStatus;
int resultRead = ReadIgnition(resultStatus);

I guess if you would pick the value from a predefined table it would look something like this:
typedef struct 
{
    int (*ReadIgnition)(ubyte &ignitionStatus);
    int (*ReadSomething)(ubyte &ignitionStatus);
} TBootPointers;

and then do 
const TBootPointers *bootPointers = 0xFC00;
bootPointers->ReadIgnition(resultStatus);

Or maybe this can be a clue:
int (*ReadIgnition)(ubyte &ignitionStatus);
ReadIgnition =  (int (*)(ubyte &))  (*(*int)0xFC02);

best regards
Johan Wallström
Elektronik Design AB
060-169550

----- Original Message ----- 
  From: Bengt Ragnemalm 
  To: ICC-AVR discussion list 
  Sent: Friday, September 14, 2007 7:59 AM
  Subject: [Icc-avr] Bootloader


  Is it possible for the normal program to access functions in the bootloader (to save space)? If that is so, how do I do it in C?

   

  Best regards

  Bengt

   

  ________________________________________________________________

  Bengt Ragnemalm                        Tel +46 13 22 24 97

  Research engineer                                       FAX: +46 13 10 19 02

  Linköpings Universitet                                mailto:bengt.ragnemalm at imt.liu.se

  Inst. för Medicinsk Teknik Internet:        http://www.imt.liu.se

  S-581 85 Linköping SWEDEN

   

   



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