hw8sol

hw8sol - CSE140 Fall 2006 Homework #8 CSE140 Homework #8 -...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CSE140 – Fall 2006 Homework #8 CSE140 Homework #8 - Solutions 5.12 XOR(X,Y) = XY’+X’Y => If X=1 => XOR(X,Y) = Y’ If X=0 => XOR(X,Y) = Y Therefore, XOR gate could be used as a controllable inverter (in this example, the control input is X. If X=1, then the output will be Y’, If X=0, then the output will be Y). The main functionality of the ALU can be broken into four parts: 0, arithmetic, logic, and 1. In order to share one adder for arithmetic commands of ALU, you need to decide when each input must be inverted. The following table is part of the ALU table which deals with arithmetic operations. S2 S1 S0 ALU Operation 0 0 1 Fi=B minus A 0 1 0 Fi=A minus B 0 1 1 Fi=A plus B Based on this table, we can decide for each operation which of the inputs must be inverted. We should also determine the carry which is given to the adder. S2 S1 S0 ALU Operation Adder’s Input1 Adder’s Input2 A’s Inversion B’s Inversion Adder’s Carry In 0 0 1 Fi=B minus A A’ B 1 0 1 (operation is -)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

hw8sol - CSE140 Fall 2006 Homework #8 CSE140 Homework #8 -...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online