HC08 C Beginners Guide for CodeWarrior in Variables Declaration

[el_shaka]

Hi everybody!!

Does anybody knows about a document where it explains the way of how do special Things using C and codewarrior. Ive been using MC908AP8 for quite a while using only assembler.

Now im having some problems because i do not know how to use C with Assembler, specifically with variable declarations and how to refer to an specific memory location as a variable.

Assume that i have a C code and I invoce a function in ASM. This function stores a result in, to say, $81, now i need that in my  C code, but i have no idea how to do it. Ive tried:

count = 0x81; (failed)

#define count unsigned int 0x81; (failed)

and some other ways that ive found in the Hepl and in the forum.

An example of my code is right here


void main (void)
{
   asm_code();                      // (It couts something and stores the final count in $81, it wont be over FF )
   count = ????????????; ( I want to say that count = $81)
}
 
Thanks a lot, an explanation, a link to some tutorial, a link to any manual, anything, please.

[el_shaka]

Actually what i did was

count = @0x0081

Thanks a lot.

[B_Conf]

Hello,
       I hope that the next code give you an example and you can resolve tha task:

byte aux[3];       // This is the declaration in C

asm{                                     
      LDHX #@aux                 
  adquiere:
       lda Some_Var    
       sta ,X                   
       incx                      
       cpx #@aux+3           
       bne adquiere            
                                 
  }
    I load the direction of aux in HX, but if I´not wrong if you put @aux you 've got the value of aux[0], @aux+1 value of aux[1] and so on.
  Try this:
    mov @aux,@count or something else.

Best regards
Pablo.

[xiefei]

try this out

count = *(int *)0x81;

[bigmac]

Hello,

Try the following approach -

Within a .c or .h file, use the following global variable definition -

extern char count @0x0081;

Then near the top of the .asm file in which you will be using the variable, include the line -

  XREF  count

Then simply refer to the variable name as required.

Regards,

Mac