I intend to migrate from Cortex M4 to Cortex R5F. As I understand both the CPUs seem very similar in a lot of aspects MPU, instruction set and yet is very different from the other. I am using ARM-CLANG as a compiler so I am not worried about the instruction set.
I would like to know which are the major points where I would have to change my software like interrupt handling, startup (maybe ?), systick handling.. Can I get an overview with this information ?
You might find this resource useful - Cortex-R Programmer's Guide.
The exception model on the R profile is very different to M profile. So expect to need to make changes to all the things you mentioned.
You mean, the major difference is between how the NVIC and VIC works ? How does SW handing has to change for the same ?