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- Bus Interface Unit, BIU, __Continue........
Instruction Pointer:-
• It is 16-bit register, which identifies the location of the next word of instruction code that is to be fetched in the current code segment.
• IP contains an offset instead of the actual address of the next instruction.
• The 20-bit address produced after addition of the offset stored in IP to segment base address in the CS is called the Physical address of the code byte.
The Queue:-
• The last section of BIU is the FIFO group of registers called a queue. It is basically a group of registers.
• This arrangement makes possible for the BIU to fetch the instruction byte while EU is decoding an instruction or executing an instruction which does not require use of buses.
• This arrangement is called pipelining.
• This is done to speed up the program execution.