This is the code I timed:
 for (i=0; i<16; i++)
    {
       temp_array1[i] = array1[i];
       temp_array2[i] = array2[i];
    }

All of the arrays are 32 bit float.

I was quite surprised that it took so long.  The above C code generates
about 70 instructions in assembler.  With a 1 Mhz instruction clock, the
processor should execute about 15,000 instructions in 66 ms.  Even going
through the loop 16 time shouldn't produce anywhere near that number of
instructions.

I am starting to think that I could write an inline assembler routine that
would just move the contents without all the array addressing and stuff.  On
an 18F4552, I should be able to expect the array contents to be contiguous.

Bruce Partridge
http://www.rebreather.ca

> It can't take 66ms just to *COPY* the arrays. You must be
> doing something else also. Couldn't you just clear GIE during
> the actual *copying* of the data, then re-enable GIE and go on
> doing that other stuff that probably takes the most part of the
> 66 ms, I guess. Just copying would at most be a number of MOVFF
> instructions, and at 4Mhz take the double number of microseconds
> (plus the GIE handling stuff).
>
> Jan-Erik.
>

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