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25521MMX instructions?

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  • warren_d_smith31
    Mar 29, 2014
      Say I have an array A[0..N-1] of N bytes, where you may assume N is divisible by 8.  I also have a function f mapping bytes to bytes,
      defined by some 256-byte array f[0..255] of constants.

      I want to do this:
      for(i=0 to N-1){   B[i] = f[A[i]];   }

      or perhaps this in-place version of the same thing:
      for(i=0 to N-1){   A[i] = f[A[i]];   }

      I there a way to do this a lot faster than the naive method, by taking advantage of MMX instructions? Even better, is there a way to access that power directly in non-assembly languages?

      There are other things that could be done fast to arrays of bytes with such instructions I suppose.  If one knew how.