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Altera_Forum
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15 years ago

Code in tightly coupled memory

Hi all, I placed a function in a section different from the main code. More exactly, my code is mapped to sdram and I linked a function testcall() into a tightly coupled memory section which I pr...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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Linker places in TCM all data you tell him to place there.

Have you specified any?

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I don't know how. Do you mean that following lines of code ? If yes, where it belongs ?

# Locate the exception stack to tightly coupled data memory.

set_setting hal.linker.enable_exception_stack TRUE

set_setting hal.linker.exception_stack_memory_region_name tightly_coupled_data_memory.

aset_setting hal.linker.exception_stack_size 1024

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If ISR function is that short I wouldn't expect great performance improvements with TTC. Probably most of the performance losses are due to ISR dispatcher.

For longer functions I REALLY DO have about 30% execution speed improvements.

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So there are no performance improvements expected ? My program code isn't that big and the cache size is 8kbyte. I'm thinking that the ISR already lies in the on-chip ram. What can I expect when i use a seperated expection stack ? The paper mentioned some overhead. Is the tightly coupled data memory only for a seperated exception stack needed ?

Thanks

Regards,