address dependent code?

[Matías Perret Cantoni]

Hello! I've found that for compiling ubldr I need to specify the address
where it will be loaded and executed, and I'd like to know more about this.
It's the first time I find that I need to specify a physical address on
compile time.

I'm sure it's kind of a whole specific programming field, so can you point
out some material that I can read about this? Any info about this will be
appreciated!

Thanks in advance.

Regards, Matias.