1. I want to know what happens when MCU powered up specific to cortex M4.
2. I have attached one keil program using TM4C123GH6PM. Its basic program to start working.
3. TM4C123GH6PM has 16Mhz internal OSC

4. I had read that flash/ram in M4 are arranged in below sequence:

Flash-> test+lireal , read only data , copy of ram data section
Ram -> Data section , bss section , heap , stack


5. According to me the exact sequence is:

Power up or any reset -> Internal clock 16Mhz init -> All peripheral/system register assigned default values -> bss section assign zero value -> ram data section assigned values from flash -> PC goes to reset handler

 

You must yourself write (or copy) every single byte of the program that is executed at power-up or any other time.

Your item (5) looks about right.