[Zlib-devel] [5/8][RFC V3 Patch] Add an Alpha MAX version of Adler32

[Jan Seiffert]

Alpha also had a little SIMD extention called MAX avail. since the
21264 aka. ev6 (and later in the 21164pc aka pca56).
We are missing a nice packed mul, but we have a pixel error
instruction (sum of absolute difference), and byte-halfword unpack
instructions so we can build something.

Thanks to Mike Frysinger, i could test the code on an Alpha.
And here the numbers:
an Alpha EV68 with MAX used (which means BWX is used for the original code)
        -------- orig ------
               a: 0x0CB4B676, 10000 * 160000 bytes     t: 3646 ms
               a: 0x25BEB273, 10000 * 159999 bytes     t: 3294 ms
               a: 0x733CB174, 10000 * 159998 bytes     t: 3335 ms
               a: 0x1144AF76, 10000 * 159996 bytes     t: 3400 ms
               a: 0x3F4ECB8A, 10000 * 159992 bytes     t: 3351 ms
               a: 0x1902A382, 10000 * 159984 bytes     t: 3369 ms
        -------- MAX ------
               a: 0x0CB4B676, 10000 * 160000 bytes     t: 1953 ms
               a: 0x25BEB273, 10000 * 159999 bytes     t: 1948 ms
               a: 0x733CB174, 10000 * 159998 bytes     t: 1963 ms
               a: 0x1144AF76, 10000 * 159996 bytes     t: 1962 ms
               a: 0x3F4ECB8A, 10000 * 159992 bytes     t: 1958 ms
               a: 0x1902A382, 10000 * 159984 bytes     t: 1964 ms
        speedup: 1.866871
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