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

22. Binary Incrementer

24. Arithmetic Circuit

25. 4-Bit Arithmetic Circuit

26. Arithmetic Circuit Function Table

27. 4-Bit Arithmetic Circuit

28. Logic Micro operations

29. Special Symbols

30. 16 Logic Micro operations- Part 1

31. 16 Logic Micro Operations – Part 2

32. Hardware Implementation

33. One Stage of Logic Circuit

34. Shift Micro Operations

35. Logical Shift Example

36. Circular Shift Example

37. Arithmetic Shift Example

38. Shift Micro Operations

39. Shift Hardware Implementation

40. 4-Bit Combinational Circuit Shifter