1. Control & Microprograms Online Appendix C

2. Implementation
What is
“Control”

3. State Machine
State machine describing control signals

4. Hard Wired Control
Machine can be hard wired to take in OP and state, produce
Control signals
Next state

5. Hard Wired Control
OP + State = Behavior + Next state

6. Microprogram Microprogram ADD r2, r4, r5
Turns “machine instruction” into steps
ADD r2, r4, r5
- State State State State 7

7. Microprogram Microprograms read from flash memory Can be reprogrammed

8. Microcode Patches
Microcode used in all x86 processors

9. Pros & Cons Hardcoded Microprogram Faster Fixable:
Flexible: Can simulate instructions without hardware