report(Integer to ASCII): Added part about int to ascii

1 files changed, 86 insertions, 0 deletions

diff --git a/report/report.tex b/report/report.tex
index 44265b8..0837393 100644..100755
--- a/report/report.tex
+++ b/report/report.tex
@@ -270,6 +270,92 @@ the sub-array, and access the element at the given \textit{index}.
 To swap two \textit{sub-arrays}, it simply swap their \textit{pointers} 
 in the pointer-array.
 
+\newpage
+
+\subsection{Integer to ASCII}
+\begin{wrapfigure}[11]{r}{0.4\textwidth}
+    \begin{tabular}{|c|c|c|c|c|}
+        \hline
+        \multicolumn{5}{|c|}{ASCII table :: Numeric Glyphs} \\
+        \hline
+        0 & 1 & 2 & 3 & 4 \\
+        \hline
+        $48_{10}$ & $49_{10}$ &$ 50_{10}$ & $51_{10}$ &$ 52_{10}$ \\
+        $30_{16}$ & $31_{16}$ & $32_{16}$ & $33_{16}$ & $34_{16}$ \\
+        \hline 5 & 6 & 7 & 8 & 9 \\
+        \hline
+        $53_{10}$ &$ 54_{10}$ & $55_{10}$ &$ 56_{10}$ & $57_{10}$ \\
+        $35_{16}$ & $36_{16}$ & $37_{16}$ & $38_{16}$ & $39_{16}$ \\
+        \hline
+    \end{tabular}
+    \caption{Table over numeric ASCII codes}\label{fig:ascii-table}
+\end{wrapfigure}
+
+When converting each coordinate back into \textit{ASCII},
+we use the \textbf{Euclidean algorithm} to extract each digit,
+but the result is still in binary.
+\smallskip
+
+\noindent
+To convert the binary digit to its \textit{ASCII} character,
+we simply add the \textit{ASCII} code for \texttt{0},
+which is \texttt{48} in decimal and \texttt{30} in hexadecimal.
+This works because each digit is in order in the \textit{ASCII Table}.
+\smallskip
+
+\noindent
+But the algorithm have the downside of getting each digit
+in \textit{reverse} order, means we need to start right side of the \textit{buffer} when
+adding new digits, as to not \textit{overwrite} previous digits.
+\smallskip
+
+\noindent
+So each digit needs to be shifted down to \textit{leftmost} position in memory.
+\bigskip
+
+\noindent
+To do this we used \texttt{REP MOVSB} which is a string operation in the
+\textit{x86 instructionset architecture} that performs a
+\textit{repeated byte copy operation}.
+
+\noindent
+\begin{wrapfigure}[8]{l}{0.55\textwidth}
+    \begin{tabular}{|c|c|}
+        \hline
+        \multicolumn{2}{|c|}{\texttt{REP MOVSB} :: Operands Overview} \\
+        \hline
+        Register/Input & Purpose \\
+        \hline
+        \texttt{RSI} & Source memory addresse \\
+        \texttt{RDI} & Destination memory addresse \\
+        \texttt{RCX} & Repeat Count \\
+        \texttt{DF} & Direction \\
+        \hline
+    \end{tabular}
+    \caption{Table over \texttt{MOVSB} operands}\label{fig:movsb-operands}
+\end{wrapfigure}
+
+\noindent
+It copies data from the memory location pointed to by
+the \textit{source} index register (\texttt{RSI}) to the location pointed to by
+the \textit{destination} index register (\texttt{RDI}),
+repeating this operation for a number of \textit{iterations} specified by
+the count register (\texttt{RCX}).
+\vspace{1cm}
+
+\noindent
+\texttt{RSI} and \texttt{RDI} are automatically either \textit{incremented} or
+\textit{decremented}, based on direction flag (\texttt{DF});
+when the direction flag is \textit{clear}, both pointers \textit{increment},
+and when it's \textit{set} both pointers \textit{decrement}.
+\smallskip
+
+\noindent
+This \textit{instruction} is particularly useful for bulk memory operations
+such as copying strings
+as it encodes a potentially lengthy loop into a \textit{single} instruction,
+thereby improving both code density
+
 \section{Evaluation}
 
 To evaluate whether out program works, we created three \textit{shell scripts},