Re: [avr-gcc-list] code generation

[Joerg Wunsch]

As Torsten Hahn <address@hidden> wrote:

>Hi, compiling a code like this in an interrupt handler

>extern volatile uint16_t cnt;
>
>if(!cnt--) {
>       asm("nop");
>}

>I think the code in lines 5, 6, 7 and 8 is a bit inefficient. Why 
>storing the regs to sram and loading them back again ?

Because you declared the variable to be `volatile'.  This prevents
/any and all/ optimizations on it.  You got what you asked for.

> How can i help 
>the compiler to do a better job there ?

Don't do that.
-- 
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/