On 2/15/07, Trent Piepho <[EMAIL PROTECTED]> wrote: > On Wed, 14 Feb 2007, Alan wrote: > > > > My comment is not very good, in fact on some cameras I need to swap the > > > > bytes > > > > to have correct JPEG data (so this is not an endianness issue I think). > > > > Maybe there is a macro to swap bytes in a buffer? I cannot find it. > > > > > > Sorry, there's a swab32, but no swab16. I misremembered. > > > > Its just called "swab" for 16bit values and is a gcc builtin/string > > function. > > The C library function swab() isn't usable in the kernel, as it's not part > of the kernel's C lib. > > Gcc doesn't have a builtin swab/bswap16 yet, maybe it will someday: > http://gcc.gnu.org/ml/gcc-patches/2006-07/msg00496.html > > The kernel does have swab64, swab32, and yes, swab16 macros! They're all > defined in the same place in asm/byteorder.h. There are architecture > optimized versions for some cases, but not for x86 and swab16 as gcc > supposedly does ok (or does it? *). > > There are three versions of the swabXX functions, a normal one, one that > takes a pointer to the data, and one that swaps the data in-place. The > more specialized versions might be faster in some cases. I don't see any > version of that swaps an array of data, like C-lib swab(), which be a lot > more useful that swab16 vs swab16p vs swab16s, IMHO.
Additionally we have some bswap* functions in dvb-apps, if it helps in some way http://linuxtv.org/hg/dvb-apps?f=15989fca7c14;file=lib/libucsi/endianops.h;style=gitweb Manu ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
