Editing Graphics processing unit (section)

=== 1970s ===
[[Arcade system board]]s have used specialized graphics circuits since the 1970s. In early video game hardware, [[Random-access memory|RAM]] for frame buffers was expensive, so video chips composited data together as the display was being scanned out on the monitor.<ref>{{cite web|last1=Hague|first1=James|title=Why Do Dedicated Game Consoles Exist?|url=https://prog21.dadgum.com/181.html|website=Programming in the 21st Century|date=September 10, 2013|url-status=dead|archive-url=https://web.archive.org/web/20150504042057/https://prog21.dadgum.com/181.html|archive-date=May 4, 2015|access-date=November 11, 2015}}</ref>

A specialized [[barrel shifter]] circuit helped the CPU animate the [[framebuffer]] graphics for various 1970s [[arcade video game]]s from [[Midway Games|Midway]] and [[Taito]], such as ''[[Gun Fight]]'' (1975), ''[[Sea Wolf (video game)|Sea Wolf]]'' (1976), and ''[[Space Invaders]]'' (1978).<ref>{{cite web|url=https://github.com/mamedev/mame/tree/master/src/mame/drivers/8080bw.c |archive-url=https://archive.today/20141121125813/https://github.com/mamedev/mame/tree/master/src/mame/drivers/8080bw.c |url-status=dead |archive-date=2014-11-21 |title=mame/8080bw.c at master 路 mamedev/mame 路 GitHub |work=GitHub }}
* {{cite web|url=https://github.com/mamedev/mame/tree/master/src/mame/drivers/mw8080bw.c|archive-url=https://archive.today/20141121125812/https://github.com/mamedev/mame/tree/master/src/mame/drivers/mw8080bw.c|url-status=dead|archive-date=2014-11-21|title=mame/mw8080bw.c at master 路 mamedev/mame 路 GitHub|work=GitHub}}
* {{cite web|url=https://www.computerarcheology.com/wiki/wiki/Arcade/SpaceInvaders|title=Arcade/SpaceInvaders – Computer Archeology|work=computerarcheology.com|url-status=dead|archive-url=https://web.archive.org/web/20140913080838/https://www.computerarcheology.com/wiki/wiki/Arcade/SpaceInvaders|archive-date=2014-09-13}}</ref> The [[Namco Galaxian]] arcade system in 1979 used specialized [[graphics hardware]] that supported [[RGB color model|RGB color]], multi-colored sprites, and [[Tile engine|tilemap]] backgrounds.<ref>{{cite web|url=https://github.com/mamedev/mame/tree/master/src/mame/video/galaxian.c|archive-url=https://archive.today/20141121114447/https://github.com/mamedev/mame/tree/master/src/mame/video/galaxian.c|url-status=dead|archive-date=2014-11-21|title=mame/galaxian.c at master 路 mamedev/mame 路 GitHub|work=GitHub}}</ref> The Galaxian hardware was widely used during the [[golden age of arcade video games]], by game companies such as [[Namco]], [[Centuri]], [[Gremlin Industries|Gremlin]], [[Irem]], [[Konami]], Midway, [[Nichibutsu]], [[Sega]], and Taito.<ref>{{cite web |title=mame/galaxian.c at master 路 mamedev/mame 路 GitHub |url=https://github.com/mamedev/mame/tree/master/src/mame/drivers/galaxian.c |url-status=dead |archive-url=https://archive.today/20141121114529/https://github.com/mamedev/mame/tree/master/src/mame/drivers/galaxian.c |archive-date=2014-11-21 |work=GitHub}}

* {{cite web |title=MAME – src/mame/drivers/galdrvr.c |url=https://mamedev.org/source/src/mame/drivers/galdrvr.c.html |archive-url=https://web.archive.org/web/20140103070737/https://mamedev.org/source/src/mame/drivers/galdrvr.c.html |archive-date=3 January 2014 }}</ref>

[[File:ANTIC chip on an Atari 130XE motherboard.jpg|thumb|Atari [[ANTIC]] microprocessor on an Atari 130XE motherboard]]
The [[Atari 2600]] in 1977 used a video shifter called the [[Television Interface Adaptor]].<ref>{{cite news|last1=Springmann|first1=Alessondra|title=Atari 2600 Teardown: What?s Inside Your Old Console?|url=https://www.washingtonpost.com/wp-dyn/content/article/2010/09/01/AR2010090103543.html|newspaper=The Washington Post|access-date=July 14, 2015|url-status=live|archive-url=https://web.archive.org/web/20150714082924/https://www.washingtonpost.com/wp-dyn/content/article/2010/09/01/AR2010090103543.html|archive-date=July 14, 2015}}</ref> [[Atari 8-bit computers]] (1979) had [[ANTIC]], a video processor which interpreted instructions describing a "[[display list]]"—the way the scan lines map to specific [[bitmapped]] or character modes and where the memory is stored (so there did not need to be a contiguous frame buffer).{{clarify|date=April 2023}}<ref>{{cite web|title=What are the 6502, ANTIC, CTIA/GTIA, POKEY, and FREDDIE chips?|url=https://www.atari8.com/node/31|website=Atari8.com|url-status=dead|archive-url=https://web.archive.org/web/20160305010645/https://www.atari8.com/node/31|archive-date=2016-03-05}}</ref> [[6502]] [[machine code]] [[subroutine]]s could be triggered on [[scan line]]s by setting a bit on a display list instruction.{{clarify|reason=passive voice is part of what makes this sentence hard to understand|date=April 2023}}<ref>{{cite journal|last1=Wiegers|first1=Karl E.|title=Atari Display List Interrupts|journal=Compute!|date=April 1984|issue=47|page=161|url=https://www.atarimagazines.com/compute/issue47/153_1_Atari_Display_List_Interrupts.php|url-status=live|archive-url=https://web.archive.org/web/20160304035625/https://www.atarimagazines.com/compute/issue47/153_1_Atari_Display_List_Interrupts.php|archive-date=2016-03-04}}</ref> ANTIC also supported smooth [[vertical scrolling|vertical]] and [[horizontal scrolling]] independent of the CPU.<ref>{{cite journal|last1=Wiegers|first1=Karl E.|title=Atari Fine Scrolling|journal=Compute!|date=December 1985|issue=67|page=110|url=https://www.atarimagazines.com/compute/issue67/338_1_Atari_Fine_Scrolling.php|url-status=live|archive-url=https://web.archive.org/web/20060216181611/https://www.atarimagazines.com/compute/issue67/338_1_Atari_Fine_Scrolling.php|archive-date=2006-02-16}}</ref>