MFRACF32 (CLA) instruction returns wrong result on TMS320F28035

Andre Meyer

Hi,

I am calculating the high resolution PWM part inside the CLA and for that i am using the MFRACF32 instruction to get the fractional part of the periode value.

Unfortunately the instruction returns sometimes a wrong fractional part.

For example:

MR0 = 334.0(float)

MFRACF32 MR1, MR0

MR1 = 0.999... --> wrong

MR0 = 333.0(float)

MFRACF32 MR1, MR0

MR1 = 0.0 --> correct

How to solve the issue?

Best regards,

André Meyer

over 8 years ago

0 Vishal_Coelho over 8 years ago

TI__Mastermind 20850 points

Hi Andre,

Can you post the exact assembly, or disassembly, for the code. I would like to see the instuction that loads 334 to MR0

0 Andre Meyer over 8 years ago in reply to Vishal_Coelho

Prodigy 50 points

Hi,

It was my mistake! I first checked the values with the watch window with "float" format which shows wrong values.
Changing the format to "Hex" shows the correct values.

Thanks

0 Ozino Odharo over 8 years ago in reply to Andre Meyer

TI__Genius 14261 points

Great to hear that you solved the issue.
-Ozino

C2000™︎ microcontrollers

C2000 microcontrollers forum

MFRACF32 (CLA) instruction returns wrong result on TMS320F28035