architecture

INTRODUCTION TO COMPUTER ARCHITECTURE

Q. Introduction to microprocessor

è The micro processor some time refers to the brain of pc and responsible for processing of the instruction which makes make up computer software it houses the cpu. Commonly known as the and such is a crucial important part of the home pc.

·        ALU- The part of cpu that deals with operations such as add sub, mul, div, integer and Boolean operation.  It receive control signal from cu telling it to carry out these operation.

·        CU- control unit control the movement of instruction in and out the processor.

It also controls the operation of ALU it consists of decoder control logic unit and a clock and ensures everything happened at the current time.

It also responsible for performing the instruction execution cycle.

è  Register array

·        This is a small amount of internal memory that is used for the quick storage and retrieval of data and instruction.

·        All processor included some common register used for specific function namely the program counter, IR, memory address register.

è System bus – This is comprised of the control bus, address bus, data bus.

·        It is used for connection between processor, memory, peripheral and transfer of data between various parts.

è Memory- memory unit is not an actual part of itself and it instead housed elsewhere on the mother board.

è Decoder- This is used to decode the instruction that make up a program when they are being processed and to determined in what action must be taken in order to process them this decision are normally taken by looking at op code of the instruction. Together with the addressing mode used.

è Timer or clock- It ensures that all process and instruction are carry out and completed at the right time.

·        Pulses are sent to the other are of the CPU at regular interval and action only accrued when a pulse detected.

è Control logic circuit- The control logic are used to create the control signals themselves which are then sent around the processor.

è Data bus – This is used for exchange of data between processor, memory peripheral and is by direction also that is allow that follow in both direction along the wire. Again the number of wire used in data bus can differ.

è Control bus- carries the signal relating to the control and coordinating of the various activities across the computer which can be sent from cu within the CPU.

è Address bus-the address bus contain the connection between the microprocessor and memory that caring two signals to the address which the cpu is processing at that time such as the location that the cpu is reading from, or writing to.

The width of address bus correspondence to the minimum address capacity of bus or the largest address within memory. That the bus can work with.

Q. Block diagram of IBM pc.

è Microprocessor -  It is the unit synonyms to cpu, cpu is used I  from traditional computer microprocessor act as a device or a group of device which do the following task .

·        Communicate with peripheral device.

·        Providing time signal.

·        Direct data flow.

·        Perform computer task as specified by the instruction in memory.

è ALU- Alu perform the computing function the processes.

·        It included the accumulator, temporary register, ALU circuit and five flask result is stored in accumulator and flask.

è Accumulator-it is 8 bit of register that is the part of it is used to store 8 bit of data and performing Arithmetical and logical operation the result of operation is stored in accumulator .

  D₇                 D₆                   D₅                D₄                  D₃                     D₂                 D₁                   D₀                

A

X

Y

C

B

N

P

L

è Flag- Flags are programmable it can used to store and transfer the data from register by using instruction. The ALU include flip flop that are set and reset according to data condition in accumulator and other register.

·        S-Flag (sign)

·        Z-flag(zero)

·        AC-flag(auxiliary  carry)

·        P- flag (priority)

·        C-flag (carry flag)

è Register section- it is basically storage device and transfer data from register by using instruction.

·        Stack pointer (SP)

·        Program counter(PC)

·        Storage register (SR)

è Time and control section – This unit is responsible for synchronies microprocessor operation as further clock pulse and to generate the control signals which are necessary from smooth communication between microprocessor and peripheral device.

Q. Boot Process in IBM pc.

·        In computing boot is the initialization of a computerized system. The system can be computer or appliances. The booting process can be “hard” after electrical power to the CPU is switched off to on. On the other hand “soft” when those powers on self test can be avoid.

·        A boot loader is a computer program that loads an os or some other system file for computer after completing of power on self test.

·        A loader is loaded into main memory such as hard disk drive. To loader load and execute the process that finalized the boot.

·        On modern general pulpous computer the boot up process can take 10 seconds and typically involve performing powering self test. Locating and initialization peripheral devices and then finding loading and starting a computer system.

·        Boot is short for boot strap it load and drive from the phrase of “pull on self up” by once boot strap.

Q. Explain CISC VS RISC.

    CISC

·        Complex Instruction Set Compound. (CISC).

·        Large no of complex instruction.

·        Low level computer.

·        Example of CISC processors’ are (a.) System / 360. (b.) VAX. (c.) PDP-11. (d.) Motorola 68000 Family.

·        Intel X86 based processor Architecture.

·        Variable length instruction.

·        Variable format.

·        Memory operand.

·        Complex operation.

Ø Advantage

·        Emphasis on hardware.

·        Includes multi clock complex instruction.

·        Small code size.

·        High cycle per second.

·        Transistor used for storing complex instruction.

Ø Disadvantage.

·        It is incorporation of older instruction sets into new generations of processor tended to force growing complexity.

·        Many specialized CISC instructions were not used frequently enough to justify their existence.

·        Run Slower.

    RISC.

·        Reduced Instruction Set Computer.(RISC).

·        Small number of instruction Bans the indirect addressing mode.

·        Retains only those instructions that can be overlapped and made to execute. In one machine Cycle or Less.

·        Single word instruction.

·        Single operator.

·        Fixed field decoding.

Ø Advantage.

·        Emphasis on software.

·        Single clock.

·        Reduced instruction only.

·        Register to register independent instruction.

·        Low cycle per second large code size.

·        Spend more transistors on memory register.

·        Example- Apple iPods/phones, Sony network walkman.

Q. CISC over RISC :-

·        The CISC approach Attempts to minimize the number of instructions per program sacrificing the number of cycles per instruction. RISC does the opposite, reducing the cycles per instruction at the cost of the number of instruction per program.

Q. DMA controller .

·        Direct Memory Access (DMA) Controller.

·        DMA used to direct memory access to input output peripherals.

·        Use for cpu intervention is not required to transfer data from one peripheral to other or i/o peripherals.

·        It is faster than cpu direct transfer.

·        DMA controller proceeds to operate the memory BUS directly without the cpu help .

·        Handshaking existence between DMA controller and device controller.

·        When the entire transfer is finished the DMA controller will interrupts the cpu.

·        EXAMPLE of DMA controller.

ü Internal memory – Internal memory.

ü Internal memory – external memory.

ü  External memory - Internal memory.

·        DMA save core MIPS because the core can operate in parallel.

·        DMA saves power because require less circuitry transfer to core to move dats.

Q. Intel 8088 vs 8086 microprocessor with diagram Explain?

    Intel 8088-:

·        Produced from 1979 to 1990s.

·        Max. cpu clock rate -> 5 MHZ to 10 MHZ.

·        Min. feature size 3µm.

·        16bit processor.

·        8 bit external Data BUS.

·        The 16 bit register and the 1 mb address.

·        This is architecturally very similar to 8086 the main difference is that there are only 8 data lines instead of 8086’s 16 lines.

·        All of the other pins of the device perform the same functions as the do with 8086 with two exceptions.

·        Performance -> 0.33 – 1 million instruction per second.

·        Program -> written for the 8086 can be run on 8088 without any changes.

1.     Uses special segment register 64 kb memory segment.

·        There are four different 64 kb segments for instructions, stack , data and extra data.

ü Code segment (cs) 16 bit register contain address64 kb segment.

ü Stack segment (SC)  16 bit register contain address64 kb segment.

ü Data segment (DS)  16 bit register contain address64 kb segment.

ü Extra segment (ES)  16 bit register contain address64 kb segment.

2.     Accumulator register consists AL and AH.Which can combine together and used as a 16 bit register AZ.

3.     Base register consists of two 8 bit register Bland BH . Which can combine together and uses as a 16 bit register BX.

4.     Count register consist of two 8 bit register CL and CH Which combine and work as 16 bit register CX.

5.     Data register consist of two 8 bit register DL and DH combine and work as 16 bit register DX.

6.     Stack pointer (SP) 16 bit register pointing to program structure.

7.     Base pointer (BS) 16 bit registers pointing to data structure.

8.     Source index. (SI) 16 bit register used for index.

9.     Destination Index (DI) 16 bit register

10.           Instruction pointer (IP) is a 16 bit register.

11.          Flags-> 16 bit register containing 9 one bit register.

                   I.            Over flow flag (OF)

                II.            Direction flag.(DF)

              III.            Interrupt enable flag (IP)

             IV.            Single strike flag (TF)

                V.            Single flag (SF)

             VI.            Zero flag (ZF)

           VII.            Auxiliary flag (AF)

        VIII.            Parity flag (PF)

              IX.            Carry flag (CF)

    Intel 8088.

·        Produced from 1979 to 1990s.

·        Max. cpu clock rate -> 5 MHZ to 10 MHZ.

·        Min. feature size 3µm.

·        16bit processor.

·        Package 40 pins.

1.     8086 processor has 8 general purpose  register.

                               I.            AX – AH/AL

                             II.            BX – BH/BL

                          III.            CX – CH/CL

                          IV.            DX – DH/DL

                            V.            SI – Source index.

                          VI.            DI- Destination index.

                       VII.            BP – Bass register.

                     VIII.            SP – Stack pointer.

2.     Segment register.

CS    DS    ES     SS

3.     Special purpose  register.

IP      CS

4.     Flag register.

CF,  PF, AF, ZF, SF,  TF,   IF, DF,   OF, 

·        The 8086 cpu organized as two separate processor called the BLU – Business Force Unit.    EU- Execution Unit.

*****************************************