Lecture 2 computer function

COMPUTER FUNCTIONT S PRADEEP KUMAR

Assistant Professor (SG)

VIT University – Chennai Campus

http://www.pradeepkumar.org

[email protected]

Computer SpecificationsProcessor Core i3

Variant 370M

Clock Speed 2.4GHz

Cache 3MB L2 Cache

System Memory 2GB DDR3

Graphics Processor Intel HD Graphics

Hard Disk 500GB SATA Disk

Ports RJ45, HDMI, USB, COM, ThunderBolt

Network Wi-Fi 802.11, Bluetooth

Random Access Memory (RAM)

Processor

Cache Memory

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Computer Function

Computer Function• Program Counter

• Contains the address of the next Instruction

• Instruction Register• Contains the address of the current instruction

• Memory Buffer Register (MBR)• contains the data to be written into memory or receives the data

read from memory.

• Memory Address Register (MAR)• specifies the address in memory for the next read or write

Computer Function• I/O Address register

• specifies a particular I/O device

• IO Buffer register• is used for the exchange of data between an I/O module and the

CPU.

• Memory Module• consists of a set of locations, defined by sequentially numbered

addresses.

• IO Module• An I/O module transfers data from external devices to CPU and

memory, and vice versa. It contains internal buffers for temporarily holding these data until they can be sent on..

Computer Function• Processor-memory

• Data may be transferred from processor to memory or from memory to processor.

• Processor-I/O• Data may be transferred to or from a peripheral device by transferring

between the processor and an I/O module.

• Data processing• The processor may perform some arithmetic or logic operation on data.

• Control• An instruction may specify that the sequence of execution be altered.

For example, the processor may fetch an instruction from location 149, which specifies that the next instruction be from location 182. The processor will remember this fact by setting the program counter to 182.Thus, on the next fetch cycle, the instruction will be fetched from location 182 rather than 150.

Computer Function

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Instruction Fetch and Execute

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Instruction Fetch and Execute

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Interrupts and their effects• Classes of Interrupts

• Program• Generated by some condition that occurs as a result of an instruction

execution, such as arithmetic overflow, division by zero, attempt to execute an illegal machine instruction,

• TimerInterrupts generated by the OS to take some special

actions • I/O

• Generated by the I/O Controllers like signals, errors, etc

• Hardware Failure• Power failure or memory parity error

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Interrupts and Instruction Cycle

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Interrupts and Instruction Cycle

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Interrupts and Instruction Cycle

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Sequential Interrupts

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Nested Interrupts

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Time Sequence of Multiple Interrupts

CONTINUED…..