gcd_22

[Niels Möller]

tg at gmplib.org (Torbjörn Granlund) writes:

> nisse at lysator.liu.se (Niels Möller) writes:
>
>   $ ./tune/speed -p 100000 -s 1-64 -t 3 -C mpn_gcd_11 mpn_gcd_22
>   overhead 4.01 cycles, precision 100000 units of 5.08e-10 secs, CPU freq 1966.75 MHz
>              mpn_gcd_11    mpn_gcd_22
>   1             #7.0459       11.0729
>   4             #2.8721        6.6946
>   7             #2.8415        7.3658
>   10            #3.3039        7.4346
>   13            #3.6084        7.8537
>   16            #4.0952        7.8193
>   19            #4.0620        8.0769
>   22            #3.9624        7.9849
>   25            #3.9169        8.0956
>   28            #4.0359        8.2084
>   31            #3.9816        8.0920
>   34            #3.9748        8.0933
>   37            #4.0041        8.0792
>   40            #3.9327        8.0656
>   43            #3.9239        8.1070
>   46            #3.9064        8.0289
>   49            #3.9143        8.0191
>   52            #4.0642        9.5547
>   55            #4.1251        9.8507
>   58            #4.2523        7.9096
>   61            #3.8440        7.8590
>   64            #3.8325        7.8398
>
> Is that right column for C code?  That's pretty good!

Yep. I take it branches in the old code were expensive...

> I reach performance of 1.5t and 2t where t is the gcd_11 time.

The above is also about 1.5t, if compared to the C gcd_11, which runs at
5.4 cycles per input bit on my machine.

I've just pushed the new gcd_22.

Regards,
/Niels

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