Representation of 8 Bit Number - 8.1.1 | 8. Hexadecimal Representation | Computer Organisation and Architecture - Vol 1
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Understanding 8-bit Numbers and Their Representation

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0:00
Teacher
Teacher

Today, we will explore how 8-bit binary numbers are represented and their conversion to hexadecimal. To start, can anyone tell me what you think an 8-bit number might represent?

Student 1
Student 1

I think it represents values using 0s and 1s, right?

Teacher
Teacher

Exactly! An 8-bit number can have combinations of 0s and 1s, which allows for 256 different values. Can anyone guess how that relates to decimal numbers?

Student 2
Student 2

Since it's 8 bits, does that mean it can represent decimal numbers from 0 to 255?

Teacher
Teacher

Correct! In binary, all bits as 1 give us the maximum value, which is 255 in decimal. Now, let's move on to converting binary to hexadecimal. Remember that each hexadecimal digit corresponds to four binary bits. Who can explain how this works?

Student 3
Student 3

We group the binary bits in sets of four, right? Like, 1111 in binary is F in hexadecimal because 15 in decimal equals F.

Teacher
Teacher

Absolutely! You all seem to be grasping this well. Just remember that this bit grouping is a handy shortcut to reduce complexity. In hexadecimal, we represent numbers from 0 to 15 using digits 0-9 and letters A-F.

Student 4
Student 4

So is 'FF' the highest value we can represent in two hexadecimal digits?

Teacher
Teacher

Yes, that’s exactly right! 'FF' equals 255 in decimal – a great example of how hexadecimal simplifies reading binary data. Let’s recap: 8 bits allow for numeric representation up to 255 and can easily convert to hexadecimal by grouping bits.

Representing Negative Integers in 8-bit Numbers

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Teacher
Teacher

Now that we understand positive values, let’s investigate how we represent negative integers in an 8-bit number system. What is one method we could use?

Student 1
Student 1

Could we use the sign-magnitude method?

Teacher
Teacher

Yes! The sign-magnitude method does break the 8 bits into one for the sign and seven for the magnitude. What happens with the sign bit?

Student 2
Student 2

If the sign bit is 0, it means the number is positive, and if it's 1, the number is negative.

Teacher
Teacher

Correct! But what’s a drawback of this method?

Student 3
Student 3

There are two representations for zero—positive zero and negative zero.

Teacher
Teacher

Right again! This can create confusion in calculations. Another method we can use is the two's complement. Who can describe how that works?

Student 4
Student 4

We flip all the bits and then add one to the result?

Teacher
Teacher

Exactly! This allows us to represent negative values simply and solves the zero representation problem. Remember that with two's complement, we can represent from -128 to +127. That's a range that efficiently utilizes our 256 combinations.

Student 1
Student 1

Got it! Negative numbers in two's complement allow clear calculations and avoid zero confusion.

Identifying Overflow Situations in 8-bit Calculations

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Teacher
Teacher

Let’s discuss a vital topic: overflow in binary calculations. What does overflow mean in this context?

Student 2
Student 2

It happens when the result exceeds the maximum value representable in 8 bits?

Teacher
Teacher

Yes! For example, if we add two positive numbers and the result is a negative number, we have an overflow. Can anyone provide an example?

Student 3
Student 3

If I add 127 and 1 using two's complement and get a result that looks like -128, that would show an overflow, right?

Teacher
Teacher

Exactly! In both cases—when adding positive numbers or conflicting signs—overflow might occur. We can check for overflow by looking at the carry into and out of the sign bit.

Student 4
Student 4

If the carry in to the most significant bit is different from the carry out, that indicates an overflow!

Teacher
Teacher

Correct! Recognizing overflow situations is essential while performing arithmetic in computing. Always check the sign and carry! So in summary, overflow happens when results don't fit within our number range.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

This section discusses how 8-bit numbers are represented in different bases, focusing on binary and hexadecimal systems, the implications of using these systems in computing, and how to represent both positive and negative integers in 8-bit format.

Standard

In this section, the representation of 8-bit numbers is explored through binary and hexadecimal systems. It highlights the conversion between these bases, the methods of representing positive and negative integers using techniques like sign magnitude and two's complement, and explains the significance of these representations in computational systems.

Detailed

Detailed Summary

This section provides an in-depth look at 8-bit number representation, specifically in binary and hexadecimal systems, and explains the conversion between these systems. It showcases the range of values representable with 8 bits, emphasizing that a total of 256 combinations are possible from all zeroes to all ones. The section also details how hexadecimal representation simplifies the readability of binary data, particularly in applications requiring more than 8 bits.

Furthermore, it delves into how positive and negative integers are represented within the 8-bit framework, noting that positive numbers range from 0 to 255, while negative number representation accounts for a different range of -128 to +127. Various representation techniques, such as sign magnitude and two's complement, are explained, including their advantages and drawbacks. Notably, the two's complement method is crucial for simplifying arithmetic calculations in binary systems, making it a preferred method in digital systems. Finally, it discusses potential issues like overflow in calculations and how to identify these errors in computational contexts.

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Audio Book

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Understanding 8 Bit Numbers

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So, the similar information I am representing in another number system which is your hexadecimal. Now, you just see what I am saying this is your 8 bit number all 0s to all 1s. So, all 1 in decimal it becomes 255 in hexadecimal it is your FF, FF means 15 F represents 15, 15 × 161 + 15 × 160. So, in that particular case we will get that this is nothing but 255 in decimal.

Detailed Explanation

An 8-bit number can represent values ranging from all 0s (00000000 in binary or 0 in decimal) to all 1s (11111111 in binary or 255 in decimal). In hexadecimal notation, 255 is represented as FF. Each digit in hexadecimal corresponds to four binary digits (bits) because 2 to the power of 4 is 16, which is the base of hexadecimal. Therefore, there’s a direct relationship between binary, decimal, and hexadecimal systems in terms of number representation.

Examples & Analogies

Imagine your house number system represents numbers through different colors: 0 to 255 corresponds to a simple color code. For example, code 0 might represent clear white (00000000), and code 255 (11111111) could represent vibrant black. Hexadecimal allows us to shorten the representation; FF becomes a shortcut that quickly indicates the maximum value.

Hexadecimal vs Binary Representation

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Now, when we are going to discuss that representation of number in computer or in your binary system or binary digit most of the time we are going to take help of hexadecimal number system because it is having one advantage. Say, when I am going to work with 32 bit number I have to write 32 bits ok all 32 bits 0 or maybe combination of 0s and 1 which is slightly difficult. Similarly when we are going to work with 8 bits we are going to write 8 bits all 0s to all 1.

Detailed Explanation

When working with binary numbers, particularly large ones like 32-bit numbers, writing out all the bits can be cumbersome. For example, a 32-bit binary number may have 32 individual digits to represent. The hexadecimal system simplifies this by condensing these representations into fewer digits—each hexadecimal digit corresponds to a group of four bits. Therefore, using hexadecimal allows for easier readability and management when dealing with binary data, especially in computing.

Examples & Analogies

Think about reading a long book versus a summary of that book. The long book (binary representation) contains all the details but might be too exhausting to flip through. The summary (hexadecimal representation), however, captures key points succinctly, making it easier to understand and refer to quickly.

Range of 8 Bit Numbers

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Now, how to represent integers? So, in that particular case we are talking about the number system. Now, say if I am having 8 bit numbers. So, I am having a combination of 0s and 1s and 8 bits 8 symbols. So, in that particular case we are having 256 different symbols or combinations, so this combination will go from 0 to 255.

Detailed Explanation

An 8-bit number can produce 2^8, or 256 different combinations of binary digits (from 00000000 to 11111111). This means that using 8 bits, we can represent numbers ranging from 0 (all bits 0) to 255 (all bits 1). This range is significant because it dictates how many individual values we can represent with 8 bits.

Examples & Analogies

Consider a simple lock with an 8-digit combination, where each digit can be either 0 or 1 (like a light switch). Each different arrangement of switches (binary combinations) represents a unique lock. With 8 switches, you can have 256 unique combinations to create various locks that either open (decimal 1) or stay locked (decimal 0).

Positive and Negative Numbers

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Ok, so if we are going to represent only positive numbers then what will happen I can use all those 256 character to represent positive numbers from 0 to 255, but if you are going to consider about negative number also this is the number line this is 0 and this is your positive side and this is your negative side.

Detailed Explanation

When using an 8-bit representation, if we only consider positive numbers, all 256 combinations can be used to represent values from 0 to 255. However, if we want to account for negative numbers, we must set aside some of those combinations. Typically, the range of representable numbers in signed 8-bit integers uses one bit for the sign (positive or negative), meaning the range shifts from 0 to +127 for positive numbers and -128 to 0 for negative numbers.

Examples & Analogies

Imagine a balanced scale. If the left side represents negative numbers and the right represents positive ones—consider that the scale can tip in both directions. By using one side to depict negatives, you lose some space that could depict greater positive values, hence why adding depth (negative values) limits the maximum positive capacity of the scale.

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • 8-bit representation enables flexibility but has limits on value range (-128 to +127 with two's complement).

  • Hexadecimal representation simplifies the representation of binary values.

  • Identifying overflow is crucial in computational systems for maintaining accuracy.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • FF in hexadecimal is equivalent to 255 in decimal.

  • The binary representation of 41 is 00101001.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • In binary we show using bits, 0s and 1s, they form the scripts!

📖 Fascinating Stories

  • Once upon a time in Binary Land, numbers danced with 0s and 1s, holding hands. They played games of addition, but when they overshot, they wrapped around, and everyone cried, 'Oh no! It's lost!'

🧠 Other Memory Gems

  • For two's complement: Flip the bits and add one, that's how negatives are done!

🎯 Super Acronyms

BITE stands for Binary and Integer two's complement, a True Example of representation!

Flash Cards

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Glossary of Terms

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  • Term: Binary Number System

    Definition:

    A system of representing numbers using only two digits, 0 and 1.

  • Term: Hexadecimal Number System

    Definition:

    A base-16 number system using digits 0-9 and letters A-F to represent values.

  • Term: Two's Complement

    Definition:

    A technique to represent negative numbers in binary, achieved by inverting bits and adding one.

  • Term: Overflow

    Definition:

    A condition occurring when a calculation exceeds the maximum limit of a representation.

  • Term: Sign Magnitude

    Definition:

    A method of representing integers where the first bit denotes the sign, and the remaining bits denote the magnitude.