Atmel CAVR-4 Manual De Usuario

CAVR-4

Special function types

Reference Guide

void f()

{

  static long next_stop = 100;

  extern void do_stuff();

  long tick;

  

  /* A critical block */

  {

    Mutex m;

    /* Read volatile variable 'tick_count' in a safe way 

       and put the value in a local variable */

    

    tick = tick_count;

  }

  

  if (tick >= next_stop)

    {

      next_stop += 100;

      do_stuff();

    }

}

C++ member functions can be declared using special function types. However, the 
following restriction apply:

Interrupt member functions must be static. When calling a non-static member 
function, it must be applied to an object. When an interrupt occurs and the interrupt 
function is called, there is no such object available.

Note: This type of directives are primarily intended to support static overlay, a feature 
which is useful in some smaller microcontrollers. The AVR IAR C/C++ Compiler does 
not use static overlay, as it has no use for it.

The function directives 

FUNCTION

, 

ARGFRAME

, 

LOCFRAME

, and 

FUNCALL

 are generated 

by the AVR IAR C/C++ Compiler to pass information about functions and function calls 
to the IAR XLINK Linker. These directives can be seen if you use the compiler option 
Assembler file (

-lA

) to create an assembler list file.

For reference information about the function directives, see the AVR® IAR Assembler 
Reference Guide.