Not really sure if this is an exact CS question. I'm reading the Patt/Patel Introduction to computing systems Powerpoint presentation and I don't understand about the program counter and instruction register format in LC-2.
On the memory pages section in chapter 5, it writes there: "Direct mode addressing gets page number from PC[15:9] and page offset from IR[8:0]." My question is, I don't understand why the format of PC and IR is in [x:y], can anyone explain it to me? I read on Wikipedia and it says that it should be base + offset, but why does the base and offset both have 2 separate values?