Assembly Language - Essay

Page 1 of 9

Assembly Language - Essay

By | November 2012
Page 1 of 9
ASSEMBLY LANGUAGE
An assembly language is a low-level programming language for a computer, microcontroller, or other programmable device, in which each statement corresponds to a single machine code instruction. Each assembly language is specific to a particular computer architecture, in contrast to most high-level programming languages, which are generally portable across multiple systems. Assembly language is converted into executable machine code by a utility program referred to as an assembler; the conversion process is referred to as assembly, or assembling the code. Assembly language uses a mnemonic to represent each low-level machine operation or opcode. Some opcodes require one or more operands as part of the instruction, and most assemblers can take labels and symbols as operands to represent addresses and constants, instead of hard coding them into the program. Macro assemblers include a macroinstruction facility so that assembly language text can be pre-assigned to a name, and that name can be used to insert the text into other code. Many assemblers offer additional mechanisms to facilitate program development, to control the assembly process, and to aid debugging. HISTORY OF ASSEMBLY LANGUAGE

Assembly languages date to the introduction of the stored-program computer. The EDSAC computer (1949) had an assembler called initial orders featuring one-letter mnemonics. Nathaniel Rochester wrote an assembler for an IBM 701 (1954). SOAP (Symbolic Optimal Assembly Program) (1955) was an assembly language for the IBM 650 computer written by Stan Poley. Assembly languages eliminated much of the error-prone and time-consuming first-generation programming needed with the earliest computers, freeing programmers from tedium such as remembering numeric codes and calculating addresses. They were once widely used for all sorts of programming. However, by the 1980s (1990s on microcomputers), their use had largely been supplanted by high-level languages, in the search...