[U-Boot] U-Boot's memory configuration

Hello

I was reading the U-Boot's README, section "Memory management". I don't quite understand, so please help me out: 1) does this section embrace various platforms and describe generic behavior of U-boot or PPC-specific? 2) it presents memory configuration, as I understand, for the case of booting from flash. How will it look when u-boot is loaded in RAM by preliminary boot code?

I specifically want to understand how memory is organized by U-Boot on ARM platform.

Sorry if question sounds silly.