Re: [avr-gcc-list] swap bits

[Klaus Rudolph]

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