1. CSCI206 - Computer Organization & Programming
Two’s Complement Multiplication
and
Fibonacci Procedure Workshop
zyBook: 8.3

2. Two’s complement multiplication
When doing two’s complement multiplication, the signs will take care of themselves.
The values (operands) must be fully “sign-extended” before operation (multiplication)!
The result of two n-bits values will have 2*n bits. Thus sign extension must be 2*n bit long.
We will discuss the topic in greater detail in Chapter 10

3. Examples
Discussions and examples are from (2/23/2017)
A 4-bit, 2’s complement example: (-1) * (-7) == 7, extending to 8 bits
(-1)
X) (-7) +)
> 7
Computer will extend the sign automatically to the full bits
becomes

4. Examples
A 4-bit 2’s complement example 3*(-5) == -15, extending to 8 bits
(3)
X) (-5) +)
> -15
Computer will extend the sign automatically to the full bits
becomes
Run the program mult.s in MARS

5. Work in groups of three (or two) on the problem of Fibonacci procedure (Activity 15)