LPC Microcontrollers中的主题 LPC55S69 FPU multiplication error (Hard floats)

LPC55S69 FPU multiplication error (Hard floats)

v_canoz — Fri, 09 Oct 2020 08:58:40 GMT

Hello,

I have a very surprising problem with LPC55S69. The hard ABI is enabled.

float a = 255.0; float b = 1.0; float res = a * b;

With this simple test case I get different results each time the function is called :

res = 0.407566 res = 0.489081 res = 0.505314 ...

What can cause this?

Re: LPC55S69 FPU multiplication error (Hard floats)

converse — Fri, 09 Oct 2020 09:48:18 GMT

Can you post the whole project that reproduces this?

Re: LPC55S69 FPU multiplication error (Hard floats)

v_canoz — Fri, 09 Oct 2020 14:05:19 GMT

Hi,

Further testing showed that it's due to a stack corruption. Don't know why yet, but now I'm confident it is not related to the FPU.
Sorry for disturbing!