4-bit computing: Difference between revisions

Revision as of 21:45, 24 January 2023

Revision as of 23:14, 6 March 2023

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The [[Rockwell PPS-4]] was another early 4-bit processor, introduced in 1972, which had a long lifetime in handheld games and similar roles. It was steadily improved and by 1975 been combined with several support chips to make a one-chip computer.<ref>{{cite web |url=http://www.antiquetech.com/?page_id=796 |title=Rockwell PPS-4}}</ref>

The 4-bit processors were programmed in [[assembly language]] or [[Forth (programming language)|Forth]], e.g. "MARC4 Family of 4 bit Forth CPU"<ref name="UT_Forth"/> (which is now discontinued) because of the extreme size constraint on programs and because common programming languages (for [[microcontrollersmicrocontroller]]s, 8-bit and larger), such as the [[C (programming language)|C programming language]], do not support 4-bit data types (C, and [[C++]], and more languages require that the size of the [[character (computing)#char|<code>char</code>]] data type be at least 8 bits,<ref name="ISOIEC9899_1999_1"/> and that all data types other than bitfields have a size that is a multiple of the character size<ref name="ISOIEC9899_1999_2"/><ref name="Cline"/><ref name="CPP"/>).

The 1970s saw the emergence of 4-bit software applications for mass markets like pocket calculators. During the 1980s 4-bit microprocessor were used in [[handheld electronic games]] to keep costs low.