Scribd
Upload
112 views11 pages

Ascii: Assembly Language Programming by Xorpd

ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard used to represent text and symbols as numbers. It assigns each letter, digit, punctuation mark, and control code a unique 7-bit value. Originally created for teleprinters, ASCII became a worldwide standard in 1963 and is still commonly used today. The first 128 characters (from decimal 32 to 127) contain basic Latin letters, numbers, and punctuation, while lower values are reserved for control codes.

Uploaded by

CCodeTEsla Sam
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
112 views11 pages

Ascii: Assembly Language Programming by Xorpd

ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard used to represent text and symbols as numbers. It assigns each letter, digit, punctuation mark, and control code a unique 7-bit value. Originally created for teleprinters, ASCII became a worldwide standard in 1963 and is still commonly used today. The first 128 characters (from decimal 32 to 127) contain basic Latin letters, numbers, and punctuation, while lower values are reserved for control codes.

Uploaded by

CCodeTEsla Sam
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 11

ASCII

Assembly language programming


By xorpd xorpd.net
 We will study some standard ways to
represent text as numbers.
 So far we have represented in our programs:
◦ Numbers.
◦ Boolean values (Bits).

 How can we represent text?


◦ How can we print letters to the console?
◦ How can the computer keep letters in memory?
 American Standard Code for Information
Interchange.

 Defines numeric values for basic symbols:


◦ The English alphabet. (Capital letters too).
◦ Digits.
◦ Punctuation symbols (!,$,#,…)
◦ Control codes.

 Every symbol is of size 7 bits.

 Worldwide standard.
 Originally created for use on teleprinters.
 Built for data communication.

http://commons.wikimedia.org/wiki/File:T100S_teleprinter.jpg
(ArnoldReinhold)

 First used commercially at 1963,


◦ As a 7-bit teleprinter code for American Telephone & Telegraph’s TWX
network.
http://commons.wikimedia.org/wiki/File:ASCII-Table.svg
 Printable symbols:
◦ Symbols that could be printed to the screen.
◦ Almost all of the interval: 0x20-0x7f.

 Control codes:
◦ Most of those are not in use today.
◦ Almost all of the interval: 0x0-0x1f
 Basic symbols:
◦ A – Z: 0x41 – 0x5a
◦ a – z: 0x61 – 0x7a
◦ 0 – 9: 0x30 – 0x39

 Special symbols:
◦ Null: 0x0
◦ Space: 0x20

◦ New line:
 Carriage return: 0xd
 Line feed: 0xa
 Standard for text representation for most of the
known writing systems.
 Has a few encoding implementations.

 UTF-8
◦ Character encoding that implements unicode.
◦ Very common.
◦ Designed for backwards compatibility with ASCII.
 The first 128 characters are the same.

 We will only discuss ASCII in this course.


◦ You could always extend to UTF-8 later, if you want.
 ASCII is a standard way to encode some very
simple symbols into 7 bits.

 Unicode is a standard way to encode almost


any known character.
◦ UTF-8 is a very common character encoding to
implement unicode.

◦ UTF-8’s 128 first symbols are the same as ASCII’s


128 first symbols.
 Study the printable part of the ASCII table.
◦ No need to learn it by heart :)

You might also like