[oe] [PATCH/RFC] qt4-embedded: tune QT_ARCH for armv6

[Eric Bénard]

Hi,

Le 04/11/2010 19:26, Holger Freyther a écrit :
> On 11/04/2010 10:52 AM, Eric Bénard wrote:
>> this is a RFC, I think it can also be used on qt 4.6.x and on armv7.
>> Setting QT_ARCH to armv6 enable some asm optimized functions in QT.
>
> Do you know the consequences of this change? E.g. in the painting
> engine unaligned memory access will be allowed. I am not sure that Nokia has
> ever benchmarked what is faster (aligned/unaligned) access. So it would be
> very interesting to know the perf difference. E.g. use qttracereply to measure it.
>
> Phil do you happen to know why unaligned access got allowed starting from
> armv6? How fast will it be?
>
in the painting engine, from what I saw in the .h, the asm optimisations are 
only enabled when using ARM RCVT compiler and not when using gcc but I have 
not checked everywhere in the code so I'm not sure of this.

Eric