Nios2_exception_illegal_inst

Hi,

Currently, my Nios II will report me NIOS2_EXCEPTION_ILLEGAL_INSTassertion.

Inside Exception Handling, Illegal Instruction 5 NIOS2_EXCEPTION_ILLEGAL_INST

Beside this, I don't have other information about this.

Does anyone know how to trigger this assertion? have an example code to trigger this assertion? some direction to solve this?

Thanks for your help