microprocessor architecture divided in The BIU has to interact with memory and of the programs and to carry out the required processing. EU & BIU. Explanation of the purpose of EU and BIU in Bus Interface Unit (BIU): The BIU interface to outside word. It provides full 16 bit. Define the jobs performed by the BIU and EU in the The functions performed by the Bus interface unit are: The BIU is responsible for the external bus.

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The with its 8-bit data bus interfaces to the 1 MB anr memory as a single bank. If you wish to download it, please recommend it to your friends in any social system.

This “real” address is called the physical address. The dead giveaway that tells you when Amazon has the best price. BIU takes care of all data and addresses transfers on the buses for the EU like sending addresses, fetching instructions from the memory, reading data from the ports and the memory as well as writing data to the ports and microproccessor memory.

Execution Unit (EU):

All the data, pointer, index and status registers are of 16 bits. Zero Flag ZF – set if the result is zero. In effect, this multiplies the segment register contents by These are set or reset by the EU on the basis of the results of some snd or logic operation. With the help of queue it is possible to fetch next instruction while current instruction is in execution.

The ajd two types of flags: There are 8 general purpose registers, i. CS register cannot be changed directly. Stack segment SS is a bit register containing address of 64KB segment with program stack. Because the next several instructions are usually in the queue, the BIU can access memory at a somewhat “leisurely” pace.


Microprocessor – 8086 Functional Units

An address within a segment is called an offset or logical address. DI register is used for holding 16 bit offset of a dataword in the Extra segment. All the data, pointer, index and status registers are of 16 bits.

The term 16 bit implies that its arithmetic logic unit, its bii registers, and most of its instructions are intended to work with 16 bit binary data. It receives and outputs all its data through BIU. By default, the processor assumes that the DI register references the ES segment in string manipulation instructions. Intel Developers kicroprocessor — http: This is a first-in, first-out storage register sometimes likened to a “pipeline”.

Fetching the next instruction while the current instruction executes is called pipelining.

Introduction to Microprocessor – ppt video online download

Which is the best book simple in microprocexsor for understanding too to study microprocessors? In this case control is to be transferred to a new nonsequential address. All general registers of the microprocessor can be used for arithmetic and logic operations.

IP address is odd, and two bytes at a time, if the CS: The EU receives program instruction codes and data from the BIU, executes these instructions, and store the results in the general registers. In simpler terms is a way to allocate memory to a program when program calls for it and deal BIU also contain an instruction queue.

Once inside the BIU, the instruction is passed to the queue. It is responsible for transmitting data, addresses and control signal on the busses. 80866 second condition occurs when the instruction to be executed is a “jump” instruction. As the name suggests microprocessro it is set then string bytes are accessed from the higher memory address to the lower memory address and vice-a-versa.


Perhaps the greatest advantage of segmented memory is that programs that reference logical addresses only can be microprocedsor and run anywhere in memory. Newer Post Older Post Home. In effect, the pays a performance penalty with every word access. This is because the logical addresses always range from h to 0FFFFh, independent of the code segment base.

Microprocessor Complete: The Execution Unit, EU

The CS register contains the segment number of the next instruction and the IP contains the offset. The 20 bit physical stack address is calculated from the SS and SP. So that the EU gets the instructions for execution in the order they are fetched.

Extra segment ES is a bit register containing address of 64KB segment, usually with program data. The important point to note, however, is that because the EU is the same for each processor, the programming instructions are exactly the same for each. The EU of tells the BIU from where to fetch instructions or data, decodes instruction su executes instructions.

Sometimes a pointer reg will be interpreted as pointing to a memory byte and at other times a memory word. This is source index register which is used to point to memory locations in the data segment addressed by DS. It is used for translating the instructions fetched from memory into a series of actions.

Due to this execution unit gets, the ready instructions in the queue and instruction fetch time is eliminated while decoding or executing an instruction EU does not require use of the buses.

Execution unit receives program instruction codes and data from the BIU, executes them and stores the results in the general registers.