Enabling Hardware Floating Point Unit in Zephyr

RE: Enabling Hardware Floating Point Unit in Zephyr

Håkon Alseth — Thu, 11 Jan 2024 10:58:13 GMT

CONFIG_CBPRINTF_FP_SUPPORT=y will only help for print functions to handle

That does indeed sound like FPU is not activated, or that something else in your system is running with the same priority (logging for instance).

Can you try to set both CONFIG_FPU=y and CONFIG_FPU_SHARING=y?

Is floating point ABI selected to be "CONFIG_FP_HARDABI"? This should be default selected.

To emit warnings on double promotion, I would recommend that you also add this:

CONFIG_COMPILER_OPT="-Wdouble-promotion"

If you log/print in the algorithm routines, please ensure that you set CONFIG_LOG=y and have selected deferred mode (CONFIG_LOG_MODE_DEFERRED)

Kind regards,

Håkon

jswcomkr — Thu, 11 Jan 2024 10:35:16 GMT

I'm already applied it.

I want to use FPU features.

I'm developing Attitude & Heading Reference System.

When I applied my algorithm using Eclipse + nRF52 SDK, update rate is over 250Hz.

But in zephyr environment, I can get only 82Hz with same code.

I think this difference is caused from FPU activation.

Håkon Alseth — Thu, 11 Jan 2024 09:33:49 GMT

Hi,

Do you need to print float variables? If yes, please see what Shahin97 suggested:

[quote user="Shahin97"]CONFIG_CBPRINTF_FP_SUPPORT=y[/quote]

If you search around on the forum, you will see many other threads on this matter as well.

Kind regards,

Håkon

jswcomkr — Thu, 11 Jan 2024 05:33:22 GMT

Thank you for reply.

But I cannot use NEWLIB CONFIG.

How can I enable these features?

Shahin97 — Wed, 10 Jan 2024 09:53:12 GMT

I believe it's enabled by default

For logging I use -

CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_CBPRINTF_FP_SUPPORT=y