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Re: [avr-gcc-list] efficient Timer Interrupts
From: |
Joerg Wunsch |
Subject: |
Re: [avr-gcc-list] efficient Timer Interrupts |
Date: |
Wed, 22 Oct 2003 17:37:10 +0200 (MET DST) |
As Torsten Hahn <address@hidden> wrote:
>The problem for me is, that using an extern (ram) var as a counter
>consumes much processor cycles (loading the var from ram,
>decrementing, write back). Is there a better (faster) solution ?
If you can sacrifice a register for it globally, you can use
register foobar asm("r2");
This might lead to a pessimisation in the remaining code. Also, if
your code consists of multiple source modules, you need to tell this
in each of them so the compiler won't accidentally reassign this
register for something else.
Note that registers 0 and 1 are required for internal gcc use.
--
J"org Wunsch Unix support engineer
address@hidden http://www.interface-systems.de/~j/