what situation will the FPCA in Cortex-M4 change?

Hi all,

I'm study Cortex-M4 recently, and try to use floating point calculation,

I read the book about that saying FPCA in control register will be set 1 after FPU work,

but I'm not sure that when will FPCA be changed after set 1, or it will never be set 0 again?

if I write a program that using FPU first, but later will not use FPU, so the Cortex-M4 will automatically set FPCA to 0?

Thanks a lot