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Xilinx PPC unexplainable cycle count

Hello,

This is what I am experiencing:

- I need to compare to code versions regarding execution speed

- comparison is done counting cycles, using the time base registers

- the only difference in code is the following: #if POST_PROC_CS_UPD // do nothing #else update_checksum(); #endif

When compiled with POST_PROC_CS_UPD = 1 the execution time of this portion is shorter, however other code that should not be affected and is executed before the above sequence is dramatically slower.

Any ideas ?

Regards, Ernest

Reply to
eascheiber
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Could be a cache effect. To see if this is true, turn off both caches and see if execution time is equal.

What is dramatic (be more specific)?

Alan Nishioka

Reply to
Alan Nishioka

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