endian-swapping

[Gabriel Paubert]

On Fri, 3 Dec 1999, Hollis R Blanchard wrote:

> 
> On Fri, 3 Dec 1999, David Edelsohn wrote:
> > 
> > 	Linux already provides macros like le16_to_cpu(), etc. for this. 
> 
> For the sake of someone (like me) who doesn't know how to use these, can you
> give an example? Just a snippet like
> 
> #include <endian.h>
> 
> #ifdef __BIG_ENDIAN
>     cpu_to_le16(blah);
> #endif
> 
> I don't know which headers are supposed to be used for this. endian.h, for
> example, does a #define __BIG_ENDIAN 4321, so __BIG_ENDIAN should *always* be
> defined... so that doesn't seem like the right header to include... but lots
> of drivers do that exact #ifdef test.
> 
> Also, the macros are in which header? I'm having trouble finding them too...

#include <asm/byteorder.h> 

Several other header files include it but you should not rely on it since
for example asm/bitops.h includes it on moost architectures but not on
Intel. 

	Gabriel.


** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/