State Flow C Action Language Bitwise Operators

I am trying to use bitwise operators to AND as well as OR an uint value with an int value in stateflow with C action language. I need to use 32 bit values but the results appear to be incorrect with 32 bit values, while 8-, 16-, and 64- bit values all seem to give correct results. Image below shows the stateflow chart and correct results using 16 bit values vs incorrect results with 32 bit values. Am I missing something? Or is this a known issue?

[Fangjun Jiang]

It makes me worried. int, uint, and, or, all keywords.

Answer 1

[Yash]

Hi Tyler,

The incorrect results in 32 bit are obtained due to saturation on integer overflow. Upon executing the model, you should notice two warnings in the Diagnostic Viewer, which are as follows:

1. "Chart containing object '...' has both C-bit operations and saturation on integer overflow enabled. To avoid unexpected results when bitwise operations produce an overflow, disable saturation on integer overflows. For more information, click here."
2. "Saturate on overflow detected."

Both warnings highlight the same concern regarding saturation on integer overflow. To resolve this, kindly proceed with the following steps:

• Open the stateflow chart.
• Right-click on the blank area within the chart and choose "Properties...".
• Uncheck the "Saturate on integer overflow" option.
• Run the model again, you should get the correct output now.

Hope this helps.