Editing Intel MCS-51 (section)

== Programming ==
There are various [[high-level programming language]] compilers for the 8051. Several [[C (programming language)|C]] compilers are available for the 8051, most of which allow the programmer to specify where each variable should be stored in its six types of memory, and provide access to 8051-specific hardware features such as the multiple register banks and bit manipulation instructions. There are many commercial C compilers.<ref>
Han-Way Huang.
[https://books.google.com/books?id=PnXNNGG_jMMC "Embedded System Design with C8051"].
p. 238.
</ref> [[Small Device C Compiler]] (SDCC) is a popular open-source C compiler.<ref>
{{cite book |author=Lewin A. R. W. Edwards |url=https://archive.org/details/pdfy-MKFMCCNbqENoR3Ft |title=So, You Wanna be an Embedded Engineer: The Guide to Embedded Engineering, from Consultancy to the Corporate Ladder |date=2006 |page=51|isbn=978-0-7506-7953-4 }}
</ref>
Other high level languages such as [[C++]], [[Forth (programming language)|Forth]],<ref name="camelforth">
{{cite web |author=Bradford J. Rodriguez |url=http://www.camelforth.com/page.php?4 |title=CamelForth/8051}}
</ref><ref name="bradford">
{{cite web |author=Brad Rodriguez |url=http://www.bradrodriguez.com/papers/moving7.htm |title=Moving Forth Part 7: CamelForth for the 8051}}
</ref><ref>{{cite web |url=http://www.forth.com/embedded/swiftx-embedded-systems-development-tools.html?MCU=8051 |title=8051 SwiftX Forth development |archive-url=https://web.archive.org/web/20150924014750/http://www.forth.com/embedded/swiftx-embedded-systems-development-tools.html?MCU=8051 |archive-date=2015-09-24 |url-status=dead}}</ref><ref>{{cite web |url=http://www.mpeforth.com/xc7.htm |title=MPE VFX Forth 7 cross compilers |archive-url=https://web.archive.org/web/20141023215234/http://www.mpeforth.com/xc7.htm |archive-date=2014-10-23 |url-status=dead}}</ref>
[[BASIC]], [[Object Pascal]], [[Pascal (programming language)|Pascal]], [[PL/M]] and [[Modula-2]] are available for the 8051, but they are less widely used<ref>{{Cite web |last=Agarwal |first=Tarun |date=2014-09-16 |title=Detailed Explanation about 8051 Programming in Assembly Language |url=https://www.elprocus.com/8051-assembly-language-programming/ |access-date=2024-10-21 |website=ElProCus - Electronic Projects for Engineering Students |language=en-US}}</ref> than C and [[Assembly language|assembly]].

Because IRAM, XRAM, and PMEM (read only) all have an address 0, C compilers for the 8051 architecture provide compiler-specific [[Directive (programming)|pragmas]] or other extensions to indicate where a particular piece of data should be stored (i.e. constants in PMEM or variables needing fast access in IRAM). Since data could be in one of three memory spaces, a mechanism is usually provided to allow determining to which memory a pointer refers, either by constraining the pointer type to include the memory space or by storing metadata with the pointer.