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K63F: no FPU?

Question asked by Tamas Selmeci on Nov 19, 2015
Latest reply on Nov 23, 2015 by Gabriel Harrison

Everywhere I look around I see K63F's Cortex M4 has an FPU. But there are two very disturbing facts:

 

1. KSDK uses this flag to compile itself for K63F:

-mfloat-abi=soft

This makes gcc generate software-floating point instructions, e.g. emulates the FPU (at a huge size and speed penalty).

 

2. If I use these compile options to utilize the FPU, the generated code simply doesn't run (I don't even see a single line of text on my serial console, but haven't gone deeper into the details):

-mfloat-abi=softfp -mfpu=fpv4-sp-d16

These are about to turn on FPU usage.

 

It's very suspicious to me that the information sources are wrong, and K63F in fact doesn't have an FPU.

 

I need some confirmation.

 

(However, I've checked the KSDK build flags for K64F too, and it includes -mfloat-abi=hard and -mfpu=fpv4-sp-d16, so it should have a working FPU.)

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