X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;ds=inline;f=methods.mtask.tex;h=db317820b360f8e7c2b87bc974b1488ab1ee27d4;hb=047ee8a13310ba90d01934827cb17c680b32a4b5;hp=5b6128d31743f024245e004200458c703daf35b7;hpb=5f23e1fc77da5ea47ca9e1f71f7c2e862e0e0df2;p=msc-thesis1617.git diff --git a/methods.mtask.tex b/methods.mtask.tex index 5b6128d..db31782 100644 --- a/methods.mtask.tex +++ b/methods.mtask.tex @@ -36,11 +36,45 @@ instance isExpr Expr \end{lstlisting} \section{Semantics} -\gls{mTask} do not behave like functions but more like -\gls{iTasks}-\glspl{Task}. When an \gls{mTask} is created it returns immediatly -and the \gls{Task} will be executed sometime in the future. \glspl{Task} can -run at an interval and they can start other tasks. -\todo{Meer uitwijden over de mTask semantiek} +The \gls{C}-backend of the \gls{mTask}-system has an engine that is generated +alongside the code for the \glspl{Task}. This engine will execute the +\glspl{mTask} according to certain rules and semantics. +\glspl{mTask} do not behave like functions but more like +\gls{iTasks}-\glspl{Task}. An \gls{mTask} is queued when either his timer runs +out or when it is started by another \gls{mTask}. When an \gls{mTask} is +queued it does not block the execution but it will return immediately while +the actual \gls{Task} will be executed some time in the future. + +The \gls{iTasks}-backend simulates the \gls{C}-backend and thus uses the same +semantics. This engine expressed in pseudocode is listed as +Algorithm~\ref{lst:engine}. All the \glspl{Task} are inspected on their waiting +time. When the waiting time has not passed the delta is subtracted and they are +pushed to the end of the queue. When the waiting has has surpassed they are +executed. When a \gls{mTask} wants to queue another \gls{mTask} it can just +append it to the queue. + +\begin{algorithm}[H] + \KwData{\textbf{queue} queue$[]$, \textbf{time} $t, t_p$} + + $t\leftarrow\text{now}()$\; + \Begin{ + \While{true}{ + $t_p\leftarrow t$\; + $t\leftarrow\text{now}()$\; + \If{notEmpty$($queue$)$}{ + $task\leftarrow \text{queue.pop}()$\; + $task$.wait $-= t-t_p$\; + \eIf{$task.wait>t_0$}{ + queue.append$(task)$\; + }{ + run\_task$(task)$\; + } + } + } + } + \caption{Engine pseudocode for the \gls{C}- and + \gls{iTasks}-backends}\label{lst:engine} +\end{algorithm} \section{Expressions} Expressions in the \gls{mTask}-\gls{EDSL} are divided into two types, namely