Lecture 6: Arithmetic Logic Unit PDF
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This document provides a detailed overview of the Arithmetic Logic Unit (ALU). It covers various aspects of ALU functions, and illustrates designs, along with examples for 4-bit and 3-bit ALUs, adders, and subtractors.
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Lecture 6: Arithmetic logic unit TO illustrate the ALU function - - TO show the ALU units - TO identify ALU circuits - ARITMATIC LOGIC UNIT 4-BIT ALU 4-BIT ADDER 4-BIT ADDER/SUBTRACTOR INSTRUCTIONS : ADD AND SUB M=0 ADD M=1 SUB If A = 0101 B = 1101 Find S3,S2,...
Lecture 6: Arithmetic logic unit TO illustrate the ALU function - - TO show the ALU units - TO identify ALU circuits - ARITMATIC LOGIC UNIT 4-BIT ALU 4-BIT ADDER 4-BIT ADDER/SUBTRACTOR INSTRUCTIONS : ADD AND SUB M=0 ADD M=1 SUB If A = 0101 B = 1101 Find S3,S2,S1,S0,C4 When M=0 When M=1 Increment circuit Instruction : INAC Decrement circuit Instruction :????? A-1 = A +2’s complement of -1 LOGIC CIRCUIT: AND ,OR,XOR,NOT INSTRUCTIONS: AND,OR,XOR,NOT 1- bit logic unit 3-BIT LOGIC UNIT 1-BIT COMPARATOR CIRCUIT A B AB ---------------------------- 0 0 0 1 0 1 0 0 0 1 0 1 1 0 0 1 1 0 1 0
