The work of an assembler is direct; translate the mnemonic ???op-codes??? into the corresponding machine
instructions.
Here is assembly language code for the program above that adds two numbers and stores the result in
a third location:
LDA 100 //Load the A-register from 100 octal = 64
ADA 101 //Add to the A-reg the contents of 101 (65)
STA 102 //Store the A-register contents in 102 (66)
Almost no one codes directly in the ones and zeros of machine language anymore. However, programmers
often use assembly language for programs that are very intimate with the details of the computer hardware, or
for programs that must be optimized for speed and small memory requirements. As an educational tool, assembly
language programming is very important, too. It is probably the best way to gain an intuitive feel for what computers
really do and how they do it.
In 1954 the world saw the first third-generation language. The language was FORTRAN, devised by John
Backus of IBM. FORTRAN stands for FORmula TRANslation. The goal was to provide programmers with
a way to work at a higher level of abstraction. Instead of being confined to the instruction set of a particular
machine, the programmer worked with statements that looked something like English and mathematical statements.
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