[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [avr-gcc-list] code generation

From: Joerg Wunsch
Subject: Re: [avr-gcc-list] code generation
Date: Mon, 27 Oct 2003 16:05:13 +0100 (MET)

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/

reply via email to

[Prev in Thread] Current Thread [Next in Thread]