Can someone help me with the Altivec instructions used for prefetching data into cache (vec_dst, vec_dstst,etc). i would like to know how the prefetch constant should be set. i want to access data from memory which some data points in between these 2 data

[mandar_s]

altivec, powerpc, mpc8641D

[alexander_yakov]

If my understanding of your question is correct, the question you asking is answered in E600 Core Reference Manual, Section 7.1.2.3.1 "Stream Engine Tags"

Here is a direct link to this document:

https://www.nxp.com/docs/en/reference-manual/E600CORERM.pdf

Have a great day,
Alexander
TIC

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[mandar_s]

Thank you for your answer

It helped me understand what vec_dst does, but i am still confused on how to calculate prefetch constatnt which has to be passed in vec_dst.

If you can help me with an example then that would be great.

[alexander_yakov]

Could you please clarify, what you mean by "prefetch constant"?

[mandar_s]

while using vec_dst instruction we have to pass 3 parameters to it i.e. address, prefetch constant(data block to be pre-fetched) and stream.

i am not able to calculated the second parameter that should be given to the vec_dst. 

i had refer this document earlier but still i am not able to clarify my doubt on vec_dst.

https://www.nxp.com/docs/en/reference-manual/ALTIVECPIM.pdf