Editing Sinclair BASIC (section)

{{Use dmy dates|date=June 2023}}
{{Use British English|date=November 2018}}
{{Short description|Dialect of the programming language BASIC}}
{{For|the implementation of BASIC used on the Sinclair QL|SuperBASIC}}

{{Infobox programming language
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| paradigm = [[Imperative programming|Imperative]]
| released = {{Start date and age|1980}}
| designer = John Grant, [[Steve Vickers (computer scientist)|Steve Vickers]]
| developer = Nine Tiles Networks,<br />[[Sinclair Research]]
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| platform = [[ZX80]], [[ZX81]], [[ZX Spectrum|ZX Spectrum, +, 128, +2, +3]], [[Timex Sinclair 2068|T/S&nbsp;2068]], [[Timex Computer 3256|TC&nbsp;3256]]
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| license = [[Proprietary software|Proprietary]]
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'''Sinclair BASIC''' is a [[dialect (computing)|dialect]] of the programming language [[BASIC]] used in the [[8-bit computing|8-bit]] [[home computer]]s from [[Sinclair Research]], [[Timex Sinclair]] and [[Amstrad]]. The Sinclair BASIC [[interpreter (computing)|interpreter]] was written by Nine Tiles Networks Ltd.<ref name="Garfield"/>

Designed to run in only 1&nbsp;KB of [[dynamic random-access memory|RAM]], the system makes a number of decisions to lower memory usage. This led to one of Sinclair BASIC's most notable features, that the keywords were entered using single keystrokes; each of the possible keywords was mapped to a key on the keyboard, when pressed, the token would be placed into memory while the entire keyword was printed out on-screen. This made code entry easier whilst simplifying the [[Parsing|parser]].

The original [[ZX80]] version supported only [[integer]] mathematics, which partially made up for some of the memory-saving design notes which had negative impact on performance. When the system was ported to the [[ZX81]] in 1981, a full [[floating-point arithmetic|floating point]] implementation was added. This version was very slow, among the slowest BASICs on the market at the time, but given the limited capabilities of the machine, this was not a serious concern. The low speed was not mainly due to an inefficient interpreter though, it was an effect of the fact that 70-80% of the machine cycles were consumed by the video hardware. So the Z80 in the ZX81 clocked at 3.25 MHz was "in effect" running at well below 1 MHz from the perspective of the BASIC system.

Performance became a more serious issue with the release of the [[ZX&nbsp;Spectrum]] in 1982, which ran too slowly to make full use of the machine's new features. This led to an entirely new BASIC for the following [[Sinclair&nbsp;QL]], as well as a number of 3rd-party BASICs for the Spectrum and its various clones. The original version continued to be modified and ported in the post-Sinclair era.