### A Theory of Computer InstructionsA Theory of Computer Instructions

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 Author Maurer, Ward Douglas Source ACM Digital Library Content type Text Publisher Association for Computing Machinery (ACM) File Format PDF Copyright Year ©1966 Language English
 Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science Abstract A computer is a set $\textit{M}$ (the memory), a set $\textit{B},$ a class of maps $\textit{S}:$ $\textit{M}$ → $\textit{B},$ known as states, and a class @@@@ of maps $\textit{T}:$ @@@@ → @@@@, known as instructions. Each instruction $\textit{I}$ has an input region $\textit{IR}(\textit{I}),$ an output region $\textit{OR}(\textit{I}),$ and affected regions $\textit{AR}(\textit{M′},$ $\textit{I}),$ for $\textit{M′}$ ⊆ $\textit{IR}(\textit{I}).$ For example, let $\textit{I}$ be the instruction (CLA Y) on the IBM 7094. If $\textit{L}$ is the location counter and $\textit{AC}$ is the accumulator, then $\textit{IR}(\textit{I})$ = $\textit{Y}$ ∪ $\textit{L}$ and $\textit{OR}(\textit{I})$ = $\textit{AC}$ ∪ $\textit{L};$ if $\textit{M′}$ is the address portion of $\textit{Y},$ then $\textit{AR}(\textit{M′},$ $\textit{I})$ is the address portion of $\textit{AC}.$ The fundamental properties of all these notions are derived, and computers are related to other models, such as sequential machines. The existence problem (how arbitrarily the input, output and affected regions of an instruction can be specified) is fully settled for countable memory $\textit{M}.$ ISSN 00045411 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 1966-04-01 Publisher Place New York e-ISSN 1557735X Journal Journal of the ACM (JACM) Volume Number 13 Issue Number 2 Page Count 10 Starting Page 226 Ending Page 235

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Source: ACM Digital Library