General question about memory addresses with underscore
The underscores are placed for your convenience when reading the addresses, since groups of four are comfortable to read, hold in short-term memory, etc, and correspond to a fairly natural amount of binary data, specifically 16 bits.

When programming in C and most assemblers, the underscores are not legal syntax; you will need to remove the underscores. Additionally, some assemblers may use a suffix h for hex rather than the 0x prefix, so you would need to use e.g. 47c000000h.