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34 lines
1.5 KiB
TeX
34 lines
1.5 KiB
TeX
\newpage
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\subsection{Control Flow}
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Control flow structures from \verb|C| like \verb|if/else| or \verb|for| are compiled into assembly mainly using jumps and conditional \verb|move|.
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By the nature of Assembly and thanks to compilers optimizing aggressively, there is no \textit{single} definitive translation of the \verb|C| control structures: The compiler may translate it very differently depending on the context of the program.
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\subsubsection{Conditional statements}
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A function using an \verb|if/else| construct to choose the maximum of $2$ numbers might compile like this:
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\inputcodewithfilename{gas}{code-examples/01_asm/}{02_max.s}
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A function computing the absolute difference $|x-y|$ using an \verb|if/else| construct, might use a conditional \verb|move| instead:
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\inputcodewithfilename{gas}{code-examples/01_asm/}{03_absdiff.s}
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\subsubsection{While Loops}
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A recursive factorial function using a \verb|do while| loop may be compiled like this:
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\inputcodewithfilename{gas}{code-examples/01_asm/}{04_factorial.s}
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\newpage
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The same function, using a \verb|while| loop instead may lead to this:
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\inputcodewithfilename{gas}{code-examples/01_asm/}{05_factorial.s}
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\subsubsection{For Loops \& Switch}
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\verb|for| loops follow the same idea as \verb|while| loops, albeit with a few more jumps.
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\verb|switch| statements are implemented differently depending on size and case values: Sparse switch statements are compiled as decision trees, whereas large switch statements may become \textit{jump tables}.
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