Atmel CAVR-4 Manuale Utente

CAVR-4

Part 2. Compiler reference

_ _task

Allows functions to exit without restoring registers. This keyword is typically used for 
the 

main

 function. 

By default, functions save the contents of used non-scratch registers (permanent 
registers) on the stack upon entry, and restore them at exit. Functions declared as 

_ _task

 do not save any registers, and therefore require less stack space. Such functions 

should only be called from assembler routines.

The function 

main

 may be declared 

_ _task

, unless it is explicitly called from the 

application. In real-time applications with more than one task, the root function of each 
task may be declared 

_ _task

.

The keyword is placed in front of the return type, for instance:

_ _task void my_handler(void);

The 

#pragma

 

type_attribute

 directive can also be used. The following declaration 

of 

my_handler

 is equivalent with the previous one:

#pragma type_attribute=_ _task

void my_handler(void);

The 

_ _task

 keyword must be specified both in the function declaration and when the 

function is defined.

_ _tiny

Controls the storage of data objects in data memory space.

The 

_ _tiny

 memory attribute overrides the default data storage of variables given by 

the selected memory model.

_ _tinyflash

Controls the storage of data objects in flash (code) memory space.

The 

_ _tinyflash

 memory attribute places objects in flash (code) memory.

Note that it is preferable to declare flash objects as constant.

0-0xFF

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255 bytes

8 bits

Data

0-0xFF

 (256 bytes)

255 bytes

8 bits

Code