1. REGISTER TRANSFER & MICROOPERATIONS By Sohaib

2. Digital System Overview  Each module is built from digital components  Registers  Decoders  Arithmetic elements  Control logic  Collection of modules is a digital system.  Modules connected by common data and control paths.

3. Microoperations  Elementary operation performed on data within one or more registers  Operation result could update same register or another register  Examples: shift, count, clear, and load  Bidirectional shift can shift left or shift right  Counter with parallel load can perform count and load.

4. Internal Hardware Organization  Can be defined by specifying  Set of registers and their functions  Sequence of microoperations performed on register data  Control that initiates the sequence of microoperations  Can use words to express sequence of microoperations, but it’s better to use a notation and symbols  Register Transfer Language

5. Registers  Capital letter sometimes followed by a number  MAR– memory address register  PC– program counter  IR– instruction register  R1,R2 – processor register 1, process register 2  Each flip-flop in a n-bit register is numbered from n-1 to 0 from left to right.

6. Register Block Diagram

7. Register Transfer

8. Control Function

9. P: R2 R1 Block Diagram

10. 2 nd Register Transfer Example

11. Bus Transfers

12. Bus System For 4 Registers

13. Bus Details

14. Memory Transfer

15. Microoperations Summary

16. Add & Subtract

17. Arithmetic Microoperations

18. Binary Adder

19. 4-bit Binary Adder

20. Binary Adder-Subtractor