[vlc-devel] [PATCH]: added proper alignments for arm_neon

Måns Rullgård mans at mansr.com
Sat Jul 28 00:14:23 CEST 2012

"Rémi Denis-Courmont" <remi at remlab.net> writes:

> Le jeudi 26 juillet 2012 16:08:55 Felix Paul Kühne, vous avez écrit :
>> the attached patch fixes alignment issues (and crashes) in our NEON code
>> for iOS.
> If I grok the binutils documentation, this patch breaks the official ARM 
> assembler syntax:
> ".align expression [, expression]
> This is the generic .align directive. For the ARM however if the first 
> argument is zero (ie no alignment is needed) the assembler will behave as if 
> the argument had been 2 (ie pad to the next four byte boundary). This is for 
> compatibility with ARM's own assembler."

Ignore that.  ARM's own assembler uses a completely different syntax
that doesn't even begin to resemble the GNU one except for the actual
instructions (and not even all of those are the same).  There is also
nothing saying a value of 2 is not compatible with whatever they had in
mind, only that zero is special.

Måns Rullgård
mans at mansr.com

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