On Sun, Nov 27, 2016 at 10:50:35PM +0100, Marius Bakke wrote:
> Leo Famulari <leo@famulari.name> writes:
> > I'm not sure, but the comment seems to indicate that we don't want to
> > use it:
> >
> > ;; According to
> > ;; http://sourceforge.net/projects/libjpeg-turbo/ ,
> > ;; "libjpeg-turbo is a derivative of libjpeg that
> > ;; uses MMX, SSE, SSE2, and NEON SIMD instructions
> > ;; to accelerate baseline JPEG compression/
> > ;; decompression", so we had better not use it
> 
> SSE is pentium III, and SSE2 was introduced in Pentium IV. MMX is even
> older. Are we really committed to supporting 15+ year old hardware?

See this earlier thread:

http://lists.gnu.org/archive/html/guix-devel/2016-07/msg01534.html

I think it's fine to use libjpeg-turbo if it can run on those older
processors, or if we decide to drop support for them.

> The NEON SIMD instruction seems to be ARM-specific and is available at
> least on Cortex A8, which is an ARMv7 design.

The extremely popular Cortex A7 [0] also has NEON SIMD.

[0] Allwinner A20