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Re: discussion reset! thumb2/thumbee code as on armv7-a

On Thursday 15 July 2010 21:11:50 Paul Brook wrote:
> Choice of ISA is independent of the ABI. Generally speaking ARM code is
>  still faster.  This is another instance of where you want multiple builds
>  of the same package within the same port, so users can choose between
> speed (-marm -O2) and size (-mthumb -Os) optimized builds.

That's still not entirely true. In a benchmark for Eigen3 library -with NEON 
enabled- the binary (bench_gemm) compiled with -mthumb gave ~0.1GFLOPS more 
(0.93, vs 0.83GFLOPS) than the one without -both on hardfp, btw. The reason is 
simple, there simply was more room in the L1/L2 caches for data and the code 
was equally fast to process them.

So, thumb is actually not a bad thing for speed either.



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