Approach to retrieving the physical memory map on different system (SFI, LEGACY,UEFI)

According to Wikipedia, in computer science a memory map is a structure of data (which usually resides in memory itself) that indicates how the memory space is laid out. In the boot process, a memory map is passed on from the firmware in order to instruct an operating system kernel about memory layout. It contains the information regarding the size of total memory, the range of specific memory space and any reserved regions, it may also provide other details specific to the architecture and platform.