Low-level programming language: Difference between revisions

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{{Short description|Programming languages similar to instruction sets}}

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{{original research|date=March 2017}}

{{Refimprove|date=July 2015}}

{{Update|date=December 2019}}

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A '''low-level programming language''' is a [[programming language]] that provides little or no [[Abstraction (computer science)|abstraction]] from a computer's [[instruction set architecture]]—commands or functions in the language map that are structurally similar to processor's instructions. Generally, this refers to either [[machine code]] or [[assembly language]]. Because of the low (hence the word) abstraction between the language and machine language, low-level languages are sometimes described as being "close to the hardware". Programs written in low-level languages tend to be relatively [[Software portability|non-portable]], due to being optimized for a certain type of system architecture.

Low-level languages can convert to machine code without a compiler or interpreter – [[second-generation programming language]]s use a simpler processor called an [[Assembly language#Assemble|assembler]] – and the resulting code runs directly on the processor. A program written in a low-level language can be made to run very quickly, with a small [[memory footprint]]. An equivalent program in a [[high-level language]] can be less efficient and use more memory. Low-level languages are simple, but considered difficult to use, due to numerous technical details that the programmer must remember. By comparison, a [[high-level programming language]] isolates execution semantics of a computer architecture from the specification of the program, which simplifies development.

==Machine code==

[[File:Digital pdp8-e2.jpg|thumb|Front panel of a PDP-8/E minicomputer. The row of switches at the bottom can be used to toggle in a machine language program.]]

[[Machine code]] is the only language a computer can process directly without a previous transformation. Currently, programmers almost never write programs directly in machine code, because it requires attention to numerous details that a high-level language handles automatically. Furthermore, it requires memorizing or looking up numerical codes for every instruction, and is extremely difficult to modify.

True ''machine code'' is a stream of raw, usually [[Binary code|binary]], data. A programmer coding in "machine code" normally codes instructions and data in a more readable form such as [[decimal]], [[octal]], or [[hexadecimal]] which is translated to internal format by a program called a [[Loader (computing)|loader]] or toggled into the computer's memory from a [[front panel]].