Hi, unfortunately it is just lack of information of MPC5777M reference manual as core description should be fully described in this RM. For MPC57xx family, no core reference manual has been issued. All separate e200zx core RMs you may find on NXP web are related to core variants use with MPC55xx/56xx.
I would ask you for entering a ticket according the procedure and I will try to find out some description of that:
How to submit a new question for NXP Support
Also it would probably require to have valid NDA (Non-disclosure agreement), please check whether your company has signed a NDA. If yes, please mention its number to the case description.
If you have not signed an agreement, please contact your local NXP Distributor Salesperson or FAE for assistance. For a listing of our distributors, refer to:
http://www.nxp.com/support/sales-and-support/distributor-network:DISTRIBUTORS