Re: Image scaling performance

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 25.02.2015 19:46, Michael Zimmermann wrote:
> oh ok so linux's div/mod/... assembler is as slow/fast as grub's code?
> Linux uses armv5>= ifdefs. Maybe we could optimized things a little :)
> About scale_nn,
> amarullz(https://plus.google.com/u/0/+AhmadAmarullah/about) wrote a
> optimized version without divs:
> loops: http://pastebin.com/MaZqWSA9
> memcpy: http://pastebin.com/iNq0V5Tw
Please try my patch (reattached here after minor fixes). The patch by 
anonymous source, sent by third-party through pastebin isn't acceptable 
from legal perspective
> this code works a little faster. I'm still questioning the efficiency
> math operations because on slow devices there are other bottlenecks of
> the same kind(like de/compression).
>
> On Wed, Feb 25, 2015 at 7:41 PM, Vladimir 'phcoder' Serbinenko
> <address@hidden> wrote:
> > ARMv7 doesn't mandate div instructions. It's a separate flag in features.
> > GRUB supports earlier CPUs as well and we use them for testing. My only test
> > machine is armv6
> >
> > Le 2015-02-25 19:38, "Michael Zimmermann" <address@hidden> a écrit
> > :
> >
> > > Why u think the native div code would crash on most devices? I support
> > > ARMv7+ only anyway.
> > >
> > > On Wed, Feb 25, 2015 at 5:23 PM, Leif Lindholm <address@hidden>
> > > wrote:
> > > > On Wed, Feb 25, 2015 at 03:45:40PM +0000, Leif Lindholm wrote:
> > > > > > > > Some technical info:
> > > > > > > > ARMv7
> > > > > > > > Linaro GCC 4.9
> > > > >
> > > > > I don't see any calls to any of the __aeabi helpers generated for this
> > > > > file with current head. Which specific Linaro toolchain are you using?
> > > > > (mine is"Linaro GCC 4.9-2014.09").
> > > >
> > > > Scratch that, I do see them. Just failing to drive the tools properly.
> > > >
> > > > /
> > > >      Leif
> > > >
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