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AdaCore / Ada_Drivers_Library

Ada source code and complete sample GNAT projects for selected bare-board platforms supported by GNAT.
BSD 3-Clause "New" or "Revised" License
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Add first draft of FE310.Performance_Monitor package. #370

Closed rod-chapman closed 4 years ago

rod-chapman commented 4 years ago

Opening Pull Request.

Closes #365

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rod-chapman commented 4 years ago

I am having trouble getting sensible values back from mhpmcounter3 - the most-significant 32 bits seem to be corrupted in some way and don't make any sense. The FE310 manual says something about the counter only really being 40 bits, so I tried to mask off the top-most 24 bits (i.e. doing andi t2, t2, 255 after the csrr t2, mhpmcounter3h instructions), but that didn't help...

Does anyone at AdaCore have way to test this?

Fabien-Chouteau commented 4 years ago

Does anyone at AdaCore have way to test this?

I have a HiFive1 revA here, but did you try with the C API first? Are there examples provided in the SDK?

rod-chapman commented 4 years ago

I tried using my own API to call to assembly code, with the same results. If I reset the counter to 0 at the start of the test, then only read the lower 32 bits, then it seems to be OK, but the upper 32 bits are all wrong...

Fabien-Chouteau commented 4 years ago

Maybe you can ask on the SiFive forums.

Fabien-Chouteau commented 4 years ago

@rod-chapman did you get more info on this?

The code looks good I am ok to merge this.

rod-chapman commented 4 years ago

OK - please go ahead and merge.

rod-chapman commented 4 years ago

I didn't get the 64-bit counters (like mhpmcounter3) to work reliably - I was still getting back garbage values for the 32 MSBs. At the moment, I am not using them, so this is not blocking me.

Fabien-Chouteau commented 4 years ago

Thank yo @rod-chapman