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Re: [avr-gcc-list] swap bits
From: |
Klaus Rudolph |
Subject: |
Re: [avr-gcc-list] swap bits |
Date: |
Tue, 21 Jan 2003 18:39:29 +0100 |
Volkmar Dierkes wrote:
I have another, but not really a good idea...perhaps :-)
> What do you mean with efficiently? bytes or time?
or IO-Pins?
Make port A output and port B input. Make a wirering
port A[0]->portB[7] ....
You need only two bytes flash for program + initialisation
and waste no registers :-)
init: ldi r16, 0xff
out ddra, r16
reverse_r16:
out porta, r16
in r16, portb
4 words flash, and 4 cycles access time.
Thats really effectiv!
Bye
Klaus
avr-gcc-list at http://avr1.org