CS 177 Recitation

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CS 177 Recitation

• 4/13/2007

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Reminders

• Lab Evaluations will be next week.
• Recitation Evaluations in 2 weeks.
• Project 5 Due on 4/18.

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Review

• What are the three parts of the von Neumann
  architecture?
• CPU
• Memory
• I/O
• What was the main advance?
• Storage of programs in main memory.

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The CPU

• What are the three main parts of the CPU?
• ALU (Arithmetic Logic Unit)
• Control Unit
• Registers
• How are they all connected?
• Bus how the data in a computer is transferred
  from one place to another.

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The Parts

• ALU
• Is where all of the operations like add,
  subtract, AND, OR, etc. are performed.
• Control Unit
• Tells data where to go
• Deciphers the machine language
• Runs the fetch-execute cycle
• Registers
• Hold data in the processor
• Very fast access

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How does it work together?

• The movement of data that is coordinated by the
  Control Unit is called the datapath.
• It always starts at the registers, goes to the
  ALU for computation, then is stored in the
  registers again.

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Knobs and Switches
Click here to launch the datapath simulator.
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Assembly Language

• Direct translation of Machine Language with 2
  differences
• Instead of 1s and 0s, assemble language uses
  abbreviations, such as ADD, SUB, MUL, DIV, LOAD,
  etc.
• Also can use labels and variables, which do not
  occur in machine language.

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Assembly vs. Machine
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Knobs and Switches and more
Click here to launch the datapath with memory
simulator.
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More about the Control Unit

• The Control Unit fetches each machine language
  instruction from memory, interprets its meaning,
  carries out the specified CPU cycle, and then
  moves on to the next instruction
• This is called the Fetch-Execute cycle

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A sample program

• What does this do?

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Knobs and Switches the finale
Click here to launch the complete simulator.
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Questions?