Opcode: Difference between revisions

Revision as of 01:51, 26 October 2024

Revision as of 18:36, 26 October 2024

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Apart from the opcode itself, an instruction normally also has one or more specifiers for operands on which the operation should act, although some operations may have ''implicit'' operands, or none at all.<ref name="Hennessy_2017"/> Depending on architecture, the operands may be [[processor register|register]] values, values in the [[call stack|stack]], other [[memory]] values, [[I/O]] ports (which may also be [[Memory-mapped I/O|memory mapped]]), etc., specified and accessed using more or less complex [[addressing mode]]s.{{citation needed|date=October 2015}} The types of operations include [[arithmetic]], data copying, [[logical operation]]s, and program control, as well as special instructions (such as [[CPUID]] and others).<ref name="Hennessy_2017"/>

[[Assembly language]], or just ''assembly'', is a [[low-level programming language]] which uses [[Assembly language#Opcode mnemonics and extended mnemonics|mnemonic]] instructions and operands to represent [[machine code]].<ref name="Hennessy_2017"/> This enhances the readability while still giving precise control over the machine instructions. Most programming is currently done using [[high-level programming language]]s,<ref name="langpop"/> which are typically easier for humans to understand and write.<ref name="Hennessy_2017"/> These languages need to be compiled (translated into assembly language) by a [[Operating system|system]]-specific [[compiler]], or run through other compiled programs.<ref name="Swanson_2001"/>

=={{Anchor|SIS}}Software instruction sets==