[U-Boot] TLB RPN is is virtual address or normal number

Hai everyone, I am using IBM Powerpc 440GX Board in board/amcc/ocotea/init.s file tlb entries littlbit under standing. But RPN(Real Page Number) means Virtual Address are Normal numbers we will take from starting(0,1,2,3,4,5,6...etc) could you give any suggestions.

#//tlbentry(EPN(Effective Page Number), SIZE, RPN(Real Page Number), ERPN(Extendable RPN), Attractives(WIMGE,Uwrx&Swrx)) #//TLB0 R4(0x4780_0250)-------R4(EPN__SIZE) #//TLB1 R5(0x4780_0000)-------R5(RPN__ERPN) #//TLB2 R6(0x00000C3F)--------R6(Attractives)