Figure 7'14 A simple 32bit instruction format

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Figure 7.14 A simple 32-bit instruction format
A Simple 32-bit Instruction Format
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Classification of Instructions

• Data movement instructions (LOAD, STORE, and
  others)
• Most frequently used, include instruction to move
  data from memory to general registers, from
  general registers to memory, between different
  general registers
• Arithmetic instructions
• There may be several different integer arithmetic
  instruction formats providing various
  combinations of register and memory access in
  different addressing modes

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• Boolean logic instructions
• Example NOT, AND , OR instructions
• Single operand manipulation instructions
• Most of them operate on the value in the
  register, but some of them operate on memory
  values as well
• Example increment a value, decrement a value or
  resetting a value.
• Bit manipulation instructions
• Provide setting and resetting of individual bits
  in a data word.

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Figure 7.17 Typical register shifts and rotates
Shift and Rotate Instructions
Page 192
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• Shift and rotate instructions
• Logical shift simply shift the data
• Arithmetic shift used to multiply or divide the
  original value by a power of 2. The leftmost bit
  is not shift.
• Program control instructions control the flow
  of a program, include jumps, branches and
  subroutine CALL and RETURN instructions.

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Figure 7.18 Operation of CALL and RETURN
instructions
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Stack instructions

• Stack instructions
• Stack data storage used to store data when the
  most recently used data will be the first needed.
  LIFO last-in, first-out structures.
• Stacks are an efficient way of storing
  intermediate data values during complex
  calculations. Example PUSH and POP instructions
• others

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Figure 7.19 Using a stack
Using a Stack
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Figure 7.22 Using a block of memory as a stack
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Buses
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Buses

• Definition a collection of electrical conductors
  (eg wires, traces) with a common purpose
• The physical connection that makes it possible to
  transfer data from one location in the computer
  system to another.
• Each wire or trace is called a line
• Typically, buses carry information from one place
  to another

From our first lecture
Ed k c
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bus
Ports
Printer Mouse Keyboard Modem
Diskcontroller
Graphicscard
Monitor Speakers
CPU
Soundcard
RAM
Networkcard
Computer
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Lines

• Each line carries a single electrical signal.
• The signal can represent one bit of a memory
  address, or sequence of data bits, or a timing
  control that turns a device on and off at the
  proper time.
• General categories
• data
• addressing
• control and power.

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Types of Buses (1 of 3)

• Point-to-point. The bus carries signals from a
  specific source to a specific destination.

Serial port
Modem
Control unit
ALU
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Types of Buses (2 of 3)

• Multipoint used to connect several points together

Computer
Computer
Computer
Computer
CPU
Memory
Disk controller
Video controller
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Types of Buses (3 of 3)

• Daisy chain

Device controller
Device
Device
Device
Terminator
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Figure 7.8 Point-to-point and multipoint buses
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Buses Inside a Computer
CPU
Data bus Address bus Control bus
Memory
I/O Module
I/O Device
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Data Bus

• Carries data between the CPU and memory or I/O
  devices
• Bi-directional
• Data transferred out of the CPU for write
  operations
• Data transferred into the CPU for read
  operations
• Typical sizes 8, 16, 32, 64 lines
• Signal names
• D0, D1, D2, D3, etc.

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Address Bus

• Carries an address from the CPU to Memory or I/O
  devices
• Unidirectional
• The address is always supplied by the CPU
• Typical sizes 16, 20, 24 lines
• Signal names
• A0, A1, A2, A3, etc.

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Control Bus

• Collection of signals for coordinating CPU
  activities
• Each signal has a unique purpose
• Typical sizes 10-20 lines
• Signals are output, input, or bi-directional
• Typical signals
• /RD (read)
• /WR (write
• CLK (clock)
• /IRQ (interrupt request)
• etc.

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Input / OutputChapter 8Sections 8.0-8.4
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Introduction

• I/O predominant factor in computers
• LMC I/O baskets correspond to a set of busses and
  registers in a hardware I/O module
• Programmed I/O (data is transferred one word at a
  time)
• Complicating factors
• Many I/O devices. Need
• Device identification
• Synchronization of operations
• I/O operations take a lot of computer time. Need
  to run them in parallel with CPU activity gt
  Operating System

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Background

• Operating System
• Manage I/O devices and data transfer operations
• Manage multiple programs

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Characteristics of Typical I/O Devices

• Characteristics of I/O devices affect computer
  performance
• Example 1 Keyboard
• Slow data is transferred one word at a time
• Two types of input expected and unexpected
  (unpredicted) ltCtrl-Cgt, ltCtrl-Alt-Delgt
• Possibly many keyboards
• Example 2 disks
• Data can be transferred in blocks fast
• Possible many disks
• Example 3 network interfaces

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Characteristics of Typical I/O Devices

• I/O operations are typically initiated by
  programs, but sometimes I/O devices need to
  initiate them too
• Devices are connected to the CPU via hardware I/O
  modules (device controllers)
• Requirements for efficient I/O. Must have
• Individual addressing of I/O devices
• Method for devices to initiate communication with
  the CPU
• Programmed I/O for slow devices non-programmed
  I/O for fast devices
• Means to handle uniformly very different devices

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Differences in I/O devices

• Data format
• One piece of data to blocks of data
• Parallel and sequential transmission
• Speed and synchronization
• Data flow
• Electromechanical requirements must be met

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Examples of I/O Devices

• Device Input/Output Date Rate (Kbytes/s)
• Keyboard Input 0.01
• Mouse Input 0.02
• Voice input (microphone) Input 0.02
• Scanner Input 200
• Voice output (speaker) Output 0.5
• Dot-matrix printer Output 1
• Laser printer Output 100
• Graphics display Output 30,000
• Local area network Input/output 200 20,000
• Optical disk Storage (I/O) 500
• Magnetic tape Storage (I/O) 2,000
• Magnetic disk Storage (I/O) 2,000

See Text Figure 8.1 - page 207
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Programmed I/O

• I/O operations are under direct control of
  software (program)
• Software initiates the I/O operation
• Disadvantage
• Slow (data is transferred one word at a time)
• Uses a lot of CPU resources
• Advantage
• Simple

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Simple I/O Configuration
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More Complex I/O Module Arrangement
Multiple devices
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I/O Configurations (1 of 2)
CPU
Keyboard Mouse Voice input (microphone) Scanner V
oice output (speaker) Dot-matrix printer Laser
printer Graphics display Local area network
Optical disk Magnetic tape Magnetic disk

• Can take many forms, e.g.,
• Sound card controller
• Disk controller

I/O module
I/O device
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I/O Configurations (2 of 2)
CPU
I/O data
I/O address
I/O control
I/O module
I/O module
I/O device
I/O device
I/O device
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Programmed I/O (1/2)
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Programmed I/O (2/2)
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Thank you