Assembly Languages and High-Level Languages Programmers write instructions in various programming languages, some directly understandable by computers and others that require intermediate translation steps. Hundreds of computer languages are in use today.
These may be divided into three general types:
1. Machine languages
2. Assembly languages
3. High-level languages
Any computer can directly understand only its own machine language. Machine language is the “natural language” of a particular computer. It is defined by the hardware design of that computer. Machine languages generally consist of strings of numbers (ultimately reduced to 1s and 0s) that instruct computers to perform their most elementary operations one at a time. Machine languages are machine dependent (i.e., a particular machine language can be used on only one type of computer). Machine languages are cumbersome for humans, as can be seen by the following section of a machine-language program that adds overtime pay to base pay and stores the result in gross pay.
+1300042774
+1400593419
+1200274027
As computers became more popular, it became apparent that machine-language programming was simply too slow and tedious for most programmers. Instead of using the strings of numbers that computers could directly understand, programmers began using English-like abbreviations to represent the elementary operations of computers. These English-like abbreviations formed the basis of assembly languages. Translator programs called assemblers were developed to convert assembly-language programs to machine language at computer speeds. The following section of an assembly-language program also adds overtime pay to base pay and stores the result in gross pay, but somewhat more clearly than its machine-language equivalent.
LOAD BASEPAY ADD OVERPAY STORE GROSSPAY
Although such code is clearer to humans, it is incomprehensible to computers until translated to machine language. Computer usage increased rapidly with the advent of assembly languages, but programming in these still required many instructions to accomplish even the simplest tasks. To speed the programming process, high-level languages were developed in which single statements could be written to accomplish substantial tasks. The translator programs that convert high-level language programs into machine language are called compilers.
