15.1. Indirect Mode

Try these first

1. 1.

   What does the indirect mode of addressing do?

   Hint

   Think about how a treasure map leads you to another location.

2. 2.

   Name the register that holds the next instruction address.

   Hint

   It's involved in tracking where the CPU is in execution.

3. 3.

   What is the purpose of the indirect mode?

   • To use direct operands only
   • To fetch operands indirectly via addresses
   • To store data in registers only

   Hint

   Remember the analogy of using another map to find what you need!

4. 4.

   True or False: Indirect addressing always uses a single memory access.

   • True
   • False

   Hint

   Think about how many steps it takes to get to the final answer.

5. 5.

   Design an hypothetical CPU instruction that uses indirect addressing to fetch an operand and outline all necessary stages in detail.

   Hint

   Consider a sequence outlining who talks to whom among registers.

6. 6.

   Compare the efficiency of indirect addressing to that of direct addressing with respect to a complex program load time.

   Hint

   Weigh the pros and cons of speed versus flexibility in memory access.