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fpu save an restore in isr

Question asked by Werner Dungs on Sep 16, 2017
Latest reply on Sep 19, 2017 by Werner Dungs

I am using mqx 4.2 . I have an isr routine which uses float variables only to hold values. No math routines are called in the isr. It seems that the fpu is used even there is no math functions, only an assign to a float variable is used. Also other float variables that is used outside of the isr in a task are changed by the isr.

It seems that the fpu registers doesn't saved and restored in isr.

 

I suppose the mqx should save and restore the fpu registers if the fpu is enabled, but it doesn't.

How can I solve the problem ?

Why the fpu is used even there is only an assign to a float variable ? 

For example vf=*((float*) p);

 

best regards

Werner

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