Imagecraft c compiler and development environment for the atmel avr

ICCV8 for AVR – C Compiler for Atmel AVRC TasksAs described in the Assembly Interface and Calling Conventions page, the compilernormally generates code to save and restore the preserved registers. Under somecircumstances, this behavior may not be desirable. For example, if you are using aRTOS (Real Time Operating System), the RTOS manages the saving and restoring ofthe registers as part of the task switching process and the code inserted by thecompiler becomes redundant.To disable this behavior, use the command #pragma ctask. For example,#pragma ctask drive_motor emit_siren....void drive_motor() { ... }void emit_siren() {...}The pragma must appear before the definitions of the functions. Note that by default,the routine main has this attribute set, since main should never return and it isunnecessary to save and restore any register for it.131