AnsweredAssumed Answered

STM32F4 -- General FPU Questions

Question asked by naphtali on Nov 10, 2014
Latest reply on Nov 10, 2014 by Clive One
I am using:
STM32F401 & STM32F407 processors
Keil uVision 4.73

I have several general questions about using the floating point unit on this processor.

1. What should I expect to happen if I try to use floats without explicitly enabling the FPU?

float var1  = 1.2;
float var2  = 3.4;
float result = 0;

result = var1 * var2;

If anyone is familiar with Keil, do we expect it to automatically use the FPU in this case?

2. How do you find the theoretical computation time for multiply/accumulate operations? I am implementing an FIR filter and need to estimate its executing time.

Outcomes