Bug#611791: [SRM] Approval for libmms_0.6-1squeeze1

[Fabian Greffrath]

Dear Hans, 

could you please comment on this? I'd like to backport this patch from
trunk to the version in Debian squeeze (libmms 0.6), because it is known
to fix the alignment bug on ARM, see
<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=611791>

 - Fabian

Am Samstag, den 19.02.2011, 16:40 +0100 schrieb Julien Cristau:
> On Mon, Feb  7, 2011 at 10:52:43 +0100, Fabian Greffrath wrote:
> 
> > +--- libmms.orig/src/bswap.h
> > ++++ libmms/src/bswap.h
> > +@@ -21,23 +21,50 @@
> > +  */
> > + 
> > + 
> > +-/* Go cheap now, will rip out glib later. *Sigh* */
> > +-#include <glib.h>
> > ++#include <stdint.h>
> > + 
> > +-/* NOTE:
> > +- * Now, to clear up confusion: LE_XX means "from LE to native, XX bits wide"
> > +- * I know it's not very clear naming (tell me about it, I
> > +- * misinterpreted in first version and caused bad nasty bug, *sigh*),
> > +- * but that's inherited code, will clean up as things go
> > +- * Oh, and one more thing -- they take *pointers*, not actual ints
> > +- */
> > +-
> > +-#define LE_16(val) (GINT16_FROM_LE (*((u_int16_t*)(val))))
> > +-#define BE_16(val) (GINT16_FROM_BE (*((u_int16_t*)(val))))
> > +-#define LE_32(val) (GINT32_FROM_LE (*((u_int32_t*)(val))))
> > +-#define BE_32(val) (GINT32_FROM_BE (*((u_int32_t*)(val))))
> > +-
> > +-#define LE_64(val) (GINT64_FROM_LE (*((u_int64_t*)(val))))
> > +-#define BE_64(val) (GINT64_FROM_BE (*((u_int64_t*)(val))))
> > ++#define SWAP_ENDIAN_16(val) \
> > ++	(val[1] | (val[0] << 8))
> 
> So this looks weird to me.  That macro looks like it's doing big endian
> to native, not swap.  And the SAME_ENDIAN_* macros smell like little
> endian to native.  Which means this is broken on BE.  Am I missing
> something?
> 
> > ++#define SWAP_ENDIAN_32(val) \
> > ++	(val[3] | (val[2] << 8) | (val[1] << 16) | (val[0] << 24))
> > ++#define SWAP_ENDIAN_64(val) \
> > ++	(val[7] | (val[6] << 8) | (val[5] << 16) | (val[4] << 24) | \
> > ++	((uint64_t)val[3] << 32) | ((uint64_t)val[2] << 40) | \
> > ++	((uint64_t)val[1] << 48) | ((uint64_t)val[0] << 56))
> > ++
> > ++#define SAME_ENDIAN_16(val) \
> > ++	(val[0] | (val[1] << 8))
> > ++#define SAME_ENDIAN_32(val) \
> > ++	(val[0] | (val[1] << 8) | (val[2] << 16) | (val[3] << 24))
> > ++#define SAME_ENDIAN_64(val) \
> > ++	(val[0] | (val[1] << 8) | (val[2] << 16) | (val[3] << 24) | \
> > ++	((uint64_t)val[4] << 32) | ((uint64_t)val[5] << 40) | \
> > ++	((uint64_t)val[6] << 48) | ((uint64_t)val[7] << 56))
> > ++
> 
> Cheers,
> Julien
> 
> 
> 
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