EVMK2EX: How 32-bit processor access Physical 40-bit Address?

Hi,

I am reading the AM5K2E0x Multicore ARM KeyStone II System-on-Chip (SoC) data sheet 

6.1 Memory Map SummaryAM5K2E0x shows that DDR3 data physical address mapped on 08 0000 0000 ~ 09 FFFF FFFF

I don't understand how to access 40-bit address data with 32-bit arm system?

The platform I used: evmk2e, processor SDK RTOS

I'd like to add code to test all 8GB DDR3 in POST

Please help!

Thanks and regards

Albert