Transcript File

Rashedul Hasan
The microprocessor is sometimes referred
to as the 'brain' of the personal computer,
and is responsible for the processing of
the instructions which make up computer
 When entire CPU (both CU & ALU) is contained
on a single tiny silicon chip, it is called
 Silicon is an element that is widely found in clay
and sand. It is a semiconductor.
 Semiconductor is material whose electrical
properties are intermediate between a good
conductor of electricity and nonconductor of
Example of Conductor &
 An example of good conductor of
electricity is copper in household wiring.
 An example of non conductor of electricity
is the plastic sheath around the wiring.
chip inside Pentium 4 processor
Inside the Microprocessor
 Arithmetic Logic Unit
 Control Unit
 Registers
 System Bus
Register contain instructions, data and
other values that may need to be quickly
accessed during the execution of a
program. This is a small amount of internal
memory that is used for the quick storage
and retrieval of data and instructions.
 ALU contain registers. Therefore Register
is a part of CPU not main memory.
 Register is high speed storage area used
to speed up the processing.
 The length of a register equals the number
of bits it can store. For example, if a
register can store 8 bits, will be referred to
8 bit register.
 Most CPU sold today have 64 bit register.
 It is also called Word size.
 The bigger the word size, the faster the
computer can process the data.
Common Registers.
 Although the number of registers varies
from computer to computer, there are
some registers common to all computer.
They are listed bellow,
 Memory address Register [MAR]: Holds
address of the active memory location.
 Memory Buffer Register [MBR]: Holds
information on its way to and from
Common Registers.
 Program Control Register [PC] : Holds
address of the next instruction to be
 Accumulator Register [A] : Accumulates
results and data to be operated upon.
 Instruction Register [I] : holds an
instruction while it is being executed.
 Input/Output Register [I/O] : Communicate
with Input & Output Devices.
System Bus
System bus is comprised of the
Control bus
Data bus
Address bus
It is used for connections between the
processor, memory and peripherals,
and transferal of data between the various
parts. The system bus is a cable which carries
data between the major components of the
computer, including the microprocessor.
System Bus
Therefore System Bus is data road ways
through which bits are transmitted within the
CPU and between CPU and other components
of motherboard.
 An 8-bit bus moves 8 bits of data at a time.
Bus width can be 8, 16, 32, 64, or 128 so far.
 Think of it as "How many passengers (bits) can
fit on the bus at once to go from one part of the
computer to another."
 Bigger number = faster transfer of data
Control Bus
The control bus carries the signals relating
to the control and co-ordination of the
various activities across the computer,
which can be sent from the control
unit within the CPU.
Data Bus
This is used for the exchange of data
between the processor, memory and
peripherals, and is bi-directional so that it
allows data flow in both directions along
the wires.
Address Bus
The address bus contains the connections
between the microprocessor and memory
that carry the signals relating to the
addresses which the CPU is processing at
that time, such as the locations that the
CPU is reading from or writing to.
System Bus
System clock rate
Processor Speed.
 Processor performs at incredible speed.
 Every processor contains a system clock which
control how fast the operations within a
computer take place.
 Instruction are fetched, decoded and executed
at proper intervals with intervals timed by a
specific number of clock cycle.
 The clock rate is the fundamental rate in cycles
per second (measured in hertz) at which a
computer performs its most basic operations
such as adding two numbers or transferring a
value from one register to another.
Clock Cycle
 One clock cycle is the time it takes to perform
one operation such as moving a byte of data
from one memory location to another.
 Normally several clock cycles are required to
fetched, decoded and executed a single
program instruction.
 Shorter the clock cycle, faster the processor.
 A single clock cycle typically lasting only a few
nanoseconds in modern microprocessors
Ways of measuring processing
 Faster clock speeds will result in faster
 For microcomputer–Megahertz &
Megahertz: a measure of frequency
equivalent to 1 million cycle [approx] per
for example, 933-MHz Pentium 3
processor can process 933 million cycles
per second.
Ways of measuring processing
Gigahertz: a billion cycles per second.
 For minicomputers & Mainframes-MIPS:
MIPS stands for million of instruction per
a mainframe can perform at 200-1200 MIPS
 For Supercomputer-Flops:
Flops stands for Floating point operations per
second. A Floating point operation is special kind
of mathematical calculation.
in case of super computer it is expressed as
Megaflops, Gigaflops & Teraflops.
Processor Speed affected by:
 System clock rate = Rate of an electronic pulse
used to synchronize processing.
(Only one action can take place between
 Measured in megahertz (MHz) where 1 MHz =
1 million cycles per second or gigahertz (GHz)
where 1 GHz = 1 billion cycles per second.
 This is what they are talking about if they say a
computer is a 2.4 GHz machine. It's clock rate is
2.4 billion cycles per second.
 Bigger number = faster processing
Architecture & Design of processor
Three main architecture or design for
microprocessor are,
 CISC : Complex Instruction Set Computing
chips, which are used mostly in PCs, can
support a large number of instruction but
at relatively low processing speed.
Architecture & Design of processor
RISC : Reduced Instruction Set Computing chips, mainly used
mostly in workstation. In opposition to CISC, the mid-1980s saw
the beginnings of the RISC philosophy. The idea here was that
the best way to improve performance would be to simplify the
processor workings as much as possible. RISC processors,
such as the IBM PowerPC processor, have a greatly simplified
and reduced instruction set, numbering in the region of one
hundred instructions or less. Changing the architecture to this
extent means that less transistors are used to produce the
processors. This means that RISC chips are much cheaper to
produce than their CISC counterparts. Also the
reduced instruction set means that the processor can execute
the instructions more quickly, potentially allowing for greater
Large (100 to 300)
Instruction Set
Small (100 or less)
Complex (8 to 20 )
Addressing Modes
Simple (4 or less)
Instruction Format
Code Lengths
Execution Cycles
Standard for most
Cost / CPU Complexity
Processor design
Processor design
Multi-core designs
A different approach to improving a computer's
performance is to add extra processors. A multicore processor is simply a single chip containing
more than one microprocessor core, effectively
multiplying the potential performance with the
number of cores.
From 2007 dual-core processors are widely
used in servers, workstations and PCs while
quad-core processors are now available for
high-end applications in both the home and
professional environments.
Multi-core designs
Keeping it straight Dual-processor (DP) systems
are those that contain two separate physical
computer processors in the same chassis. In
a dual-core configuration, an integrated circuit (IC)
contains two complete computer processors.
Usually, the two identical processors are
manufactured so they reside side-by-side on the
same die, each with its own path to the system
front-side bus. Multi-core is somewhat of an
expansion to dual-core technology and allows for
more than two separate processors.
AMD Athlon Dual core processor
Kinds of Processor.
 Intel type chips : For PC
 About 90% of microprocessor use Intel
type microprocessor.
Are mainly made by the Intel Corporation.
Other manufacturers of this type includes,
Kinds of Processor.
 Motorola-Type chips : For Macintoshes
 It is mainly made by Motorola for Apple
Macintoshes computer.
Bus Speed
Are data road ways through which bits are transmitted
within the CPU an between CPU and other
components of motherboard.
Bus Speed
 Bus Speed = the amount of data the CPU can
transmit at a time to main memory and to input
and output devices.
(Any path bits travel is a bus.)
 An 8-bit bus moves 8 bits of data at a time.
Bus width can be 8, 16, 32, 64, or 128 so far.
 Think of it as "How many passengers (bits) can
fit on the bus at once to go from one part of the
computer to another."
 Bigger number = faster transfer of data
Important Things to Know
 You want a nice match between the word size
and the bus size and the clock. It wouldn't do
any good to have a bus that can deliver data
128 bits at a time, if the CPU can only use 8 bits
at a time and has a slow clock speed. A huge
line of data would form, waiting to get off the
bus! When computers gets clogged like that,
bad things can happen to your data. It's like
people waiting to get into the theater. After a
while, some of them may leave!!
Types of BUS
Parallel Bus
Serial Bus
Parallel & Serial Bus
 Buses can be parallel buses, which carry
data words in parallel on multiple wires,
 or serial buses, which carry data in bitserial form.