ARM public key benchmark

[Niels Möller]

nisse at lysator.liu.se (Niels Möller) writes:

> I'll also try using fewer updates of the up pointer, that seems to save
> half a cycle, and could perhaps speed up addmul_1 too.

No speedup for addmul_1, unfortunately, but a saving for submul_1. Here
are new versions of both files (for mpn/arm/v6). I wonder if this
submul_1 complement trick is useful on some other platforms too, e.g.,
64-bit sparc?

Running at 3.25 and 3.9 c/l on A9:

$ GMP_CPU_FREQUENCY=1e9 ./speed -s1-1000 -f 1.2  -C mpn_addmul_1.17 mpn_submul_1.17
clock_gettime is 1.000ns accurate
overhead 8.98 cycles, precision 1000 units of 1.00e-06 secs, CPU freq 1000.00 MHz
        mpn_addmul_1.17 mpn_submul_1.17
1             19.9985      #18.7576
2             10.9929      #10.8108
3             #7.9880        8.6664
4             #6.4099        6.9205
5             #5.9251        6.3792
6             #5.4384        6.1228
7             #5.2336        5.9634
8             #4.8648        5.4154
9             #4.8359        5.2633
10            #4.5423        5.2216
12            #4.3122        4.8634
14            #4.1876        4.8111
16            #4.0881        4.6616
19            #4.0045        4.5861
22            #3.8592        4.4916
26            #3.7191        4.4362
31            #3.7194        4.3459
37            #3.6437        4.2051
44            #3.8368        4.3953
52            #3.5039        4.1120
62            #3.6497        4.2448
74            #3.6015        4.1965
88            #3.5376        4.1343
105           #3.5087        4.0832
126           #3.4988        4.1222
151           #3.4397        3.9997
181           #3.3900        3.9654
217           #3.3483        3.9500
260           #3.2994        3.9175
312           #3.3313        3.8723
374           #3.3173        3.8869
448           #3.2657        3.9315
537           #3.2799        3.9140
644           #3.3077        3.8574
772           #3.2621        3.9059
926           #3.2673        3.8317

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Regards,
/Niels

-- 
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
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