Previously it was:
ESI/RSI - SEC Core entry point
EDI/RDI - PEI Core entry point
EBP/RBP - Start of BFV
Now it is:
RAX/EAX Initial value of the EAX register
(BIST: Built-in Self Test)
DI 'BP': boot-strap processor, or
'AP': application processor
RBP/EBP Address of Boot Firmware Volume (BFV)
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9571 6f19259b-4bc3-4df7-8a09-765794883524