IPP Problem In Multithreading Applications

[flypen]

I want to use IPP in a new embedded OS, and I want to use IPP in multithreading applications. There are some problems now. I don't store the value of coprocessor registers for WMMX now, and I think perhaps it's the reason why the application doesn't work well. Should the value of coprocessor regsiters for WMMX be saved when task switch is happening?

[Ying_S_Intel]

Dear Customer,

Here is the response provided our PCA supportengeering team:

"Yes, you do have to be explicitly saved.

The following is from section 3.4.3 Buffer for Context Switch of the Intel PXA27x Processor Family Optimization Guide downloadable from:

http://www.intel.com/design/pca/applicationsprocessors/manuals/280004.htm

During context switch, the states of the process have to be saved. For the PXA27x processor, the process control block (PCB) can be large in size due to additional registers for Intel Wireless MMX Technology. To reduce context-switch latency, the internal memory can be used.

"
Hope it helps.
Thanks,
Ying S
Intel Corp.