Assembly Language

Assembly Language is a method of abstracting machine code instructions for a computer into commands recognizable by a human. Instead of dealing directly with bit sequences, programmers write programs in assembly by generating blocks of code using a small set of keywords (which are mapped to machine instructions by an assembler).

An example Hello World program written in pseudo-assembly is listed below. Original source: Assembly Language for the IBM-PC.

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.data hello_message db 'Hello, World!',0dh,0ah,'$'

.code main proc

 mov ax,@data
 mov ds,ax

 mov ah,9
 mov dx,offset hello_message
 int 21h

 mov ax,4C00h
 int 21h

main endp end main

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Assembly programs are much easier to understand than their corresponding machine code instruction streams, but they are much more difficult to comprehend than, say, the PHP Hello World program.