Accelerating random access to memory

Accelerating random access to memory

hi,

I am looking for a way to get faster memory access to, say, some random pixels in an image. I couldn't find any IPP function that dose so (or close to). Presently I am using IPPS function to compute the offset of the memory address, but IPPS doesn't support pointer arithmatic, so I still have to do the last step in a loop.
Any suggestion?

thanks,
Nizan.

Message Edited by nizanh on 02-02-2005 04:14 AM

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Hi Nizan

It is a bit unclear what you are trying to do. To get access to arbitrary pixel in image you can use

val = pSrc[y*srcStep) + x]

where x and y is pixel coordinates

Is it what you are asking about?

Regards,
Vladimir

thanks for the response.

I do access the memory with
pSrc[y*srcStep) + x].
but suppose that y & x are vectors. Access the memory through loop

for (i=1;i
is quite slow. I can speed it up if I calculate
offset[i] = y[i]*srcStep + x[i]
as vectors, using ipps functions, but I still need a loop
for (i=1;i
I want to speed it up further. If mmx/sse (and better, IPP) supportsome memory access for multiple address it would probablyboost the speed further.

thanks,
Nizan.

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