C6657 mathlib reciprocal mathlib loop buffer exception

Fawad Nackvi62335

Other Parts Discussed in Thread: MATHLIB

Hello,

I am getting a "Loop buffer exception Missed stall exception" in my C6657 EVM. I have traced this to the reciprocal function in the math library. The exception takes a random amount of time to happen. Anywhere between 5 seconds to 1 minute. I am doing the reciprocal of a 128 point vector about 2000 times a second (in addition to other processing).

I am using mathlib_c66x_3_0_1_1. I also use other math functions from the library without any issues.

Any ideas why this may be happening?

Thanks,

Fawad

over 12 years ago

0 RandyP over 12 years ago

TI__Guru* 84110 points

Fawad,

Can you provide a test case that demonstrates this exception occurring? A random exception sounds difficult to reproduce with just a high-level description, or even a more detailed one. It could be data sensitive, for example.

Have you tried re-running with the same 128-point vector to see if it always fails with a certain set of data?

Regards,
RandyP

0 Fawad Nackvi62335 over 12 years ago in reply to RandyP

Expert 1080 points

RandyP,

So further testing has shown it is the calling function that has the exception instead of the mathlib reciprocal function. I can stop the exception by compiling with less optimization (-01 instead of -02) for the calling code. So for now I will mark this issue fixed.

Thanks,

Fawad

0 RandyP over 12 years ago in reply to Fawad Nackvi62335

TI__Guru* 84110 points

Fawad,

Thanks for the update. We would still like to see a test case, if this is a case of the optimizer generating bad code.

Up to you, of course.

Regards,
RandyP

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C6657 mathlib reciprocal mathlib loop buffer exception