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On Cortex-M4F microcontrollers: is fixed point math faster or floating point?

Hi,

I am using S32K14x controllers (Coretx-M4F). It has floating point math unit. I need to perform many mathematical operations as fast as possible. Which will be faster: fixed point q16 or fixed point q32 or single precision (32 bit) floating point?

Regards,

Pramod

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  • An issue often noted with fixed point is that, aside from the actual calculations, it adds overhead & complexity to the code which needs to supply the input data and/or use the results.

    I agree.

    Another problem in using fixed point is that code won't be portable due to the use of non-standard intrinsic functions like __SMMLA etc.

    One problem in using float is that it will increase ISR entry and exit times, due to the need of saving and restoring FPU registers.

Reply
  • An issue often noted with fixed point is that, aside from the actual calculations, it adds overhead & complexity to the code which needs to supply the input data and/or use the results.

    I agree.

    Another problem in using fixed point is that code won't be portable due to the use of non-standard intrinsic functions like __SMMLA etc.

    One problem in using float is that it will increase ISR entry and exit times, due to the need of saving and restoring FPU registers.

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