Final answer:
The last two bits in a jump instruction are often zero because of the word alignment of instructions in modern processors, requiring that instruction addresses are multiples of the instruction size, typically four bytes.
Step-by-step explanation:
The question seems to be related to the fields of computer architecture or assembly language programming. In these contexts, when discussing jump instructions in a CPU instruction set, the inquiry 'Why are last two bits always 0 with jump?' refers to a common characteristic of jump instructions in some low-level programming or machine code. The alignment of instruction addresses is a typical reason for the zeroing of the last two bits in a jump instruction. Most modern processors use an instruction set that is word-aligned, which means that each instruction is a certain number of bytes long—commonly 4 bytes (or 32 bits) in length. To maintain this alignment, branches or jump instructions will target addresses that are multiples of the instruction size. Therefore, for a 4-byte aligned architecture, the last two bits of the jump address do not need to be specified because they would always be '00', indicating that the target address is word-aligned.