CS 2734 Computer Organization II

• Some comments for laboratory 3:
  • You can type help in gdb to get a list of debugger commands.
  • You can put labels in C programs just like assembly language:
    

           mylabel:
    

    Labels are useful for setting breakpoints.
  • The command set variable can be used to display the contents of a variable in C.

• Review the instruction cycle on a von Neuman machine:
  • Fetch instruction
  • Increment program counter
  • Decode instruction
  • Decode operands
  • Fetch operands
  • Execute instruction
  • Store results
  • Go to Fetch

• Continue execution of programs on one register machine.
  • Execution of a simple ADD
  • Direct addressing (the operand is an address)
  • Immediate addressing (the operand is the actual value to be used)
  • Unconditional branch (the operand becomes next PC value)
  • Conditional branch (the operand becomes next PC value if conditions are met)