From df15bb60e77b68088d724b778bd3e33856807828 Mon Sep 17 00:00:00 2001 From: Garritt McCune Date: Fri, 19 Jul 2024 13:50:44 -0500 Subject: [PATCH] Updated the Encoding Scheme section adding a 'operand mode' setting to the encoding as well changing the placement of the figures in that section. --- chapter 2.tex | 75 +++++++++++++++++++++++++++++++++------------------ 1 file changed, 49 insertions(+), 26 deletions(-) diff --git a/chapter 2.tex b/chapter 2.tex index 818b2c6..a9966ee 100644 --- a/chapter 2.tex +++ b/chapter 2.tex @@ -1,13 +1,17 @@ \chapter{Instruction Set Architecture} -\newcommand{\OpcodeTable}[4] { - \begin{tabularx}{\textwidth}{ | X | X | X | X | } - \hline - Opcode Hex & Instruction & Operand 1 & Operand 2 \\ - \hline - #1 & #2 & #3 & #4 \\ - \hline - \end{tabularx} +\newcommand{\OpcodeTable}[5] { + \noindent + \begin{minipage}{\textwidth} + \begin{tabularx}{\textwidth}{ | X | X | X | X | } + \hline + Opcode Hex & Instruction & Operand 1 & Operand 2 \\ + \hline + #1 & #2 & #3 & #4 \\ + \hline + \end{tabularx} + \paragraph{Description} #5. + \end{minipage} } \def\minY{0} \def\maxY{0.5} @@ -15,10 +19,22 @@ \usetikzlibrary{decorations.pathreplacing} -\section{Encoding Schemes} -The /r represents a byte that specifies a register. /iX is for the immediate data type, where \textit{X} defines the width, which are 8, 16, or 32 bits. - -\begin{figure}[!htb] +\section{Encoding Scheme} +There are two basic encoding schemes that the object code will take. The most basic layout is shown in Figure \ref{fig:OpShortEncodingFigure} that is used by instructions that take one or zero arguments, where the 16 most significant bits are used to encode the instruction itself. Followed by the 16 least significant bits being used to encode a numeric constant that may be interpreted as a relative address. For instructions that require two arguments the encoding scheme shown in Figure \ref{fig:OpArgEncodingFigure} is used. +%Placement info here: https://en.wikibooks.org/wiki/LaTeX/Floats,_Figures_and_Captions#Figures +\begin{figure}[h] + \begin{tikzpicture} + \draw (\minX, \minY) -- (\maxX, \minY); + \draw (\minX, \minY) -- (\minX, \maxY) node[above] {31}; %{$y$}; Note the $'s, those make something math stylized. + \draw (\maxX, \minY) -- (\maxX, \maxY) node[above] {0}; + \draw (0, \minY) -- (0, \maxY) node[above] {15}; + \draw [decorate, decoration={brace, amplitude=1em, mirror}] (\minX, -\maxY) -- (0, -\maxY) node[midway, below=1em] {Op Code (16-bits)}; + \draw [decorate, decoration={brace, amplitude=1em, mirror}] (0, -\maxY) -- (\maxX, -\maxY) node[midway, below=1em] {Near Address (16-bits)}; + \end{tikzpicture} + \caption{Short Valued Opcodes} + \label{fig:OpShortEncodingFigure} % https://www.overleaf.com/learn/latex/Referencing_Figures +\end{figure} +\begin{figure} \begin{tikzpicture} \draw (\minX, \minY) -- (\maxX, \minY); \draw (\minX, \minY) -- (\minX, \maxY) node[above] {31}; %{$y$}; Note the $'s, those make something math stylized. @@ -30,21 +46,28 @@ The /r represents a byte that specifies a register. /iX is for the immediate dat \draw [decorate, decoration={brace, amplitude=1em, mirror}] ({\maxX / 2}, -\maxY) -- (\maxX, -\maxY) node[midway, below=1em] {Source (8-bits)}; \end{tikzpicture} \caption{Register Based Opcodes} + \label{fig:OpArgEncodingFigure} % https://www.overleaf.com/learn/latex/Referencing_Figures + \paragraph{Note} How the \textit{Destination} and \textit{Source} are interpreted is dependent on the opcode and operand mode bits as shown in Figure \ref{fig:OperandModeBitPattern}. +\end{figure} +\begin{figure} + \begin{tabularx}{\textwidth}{ | X | X | X | } + \hline + Bit Pattern & Destination & Source \\ + \hline + 000 & Register & Register \\ + 001 & Register & 8 Bit Immediate \\ + 010 & Register & 32 Bit Immediate \\ + 011 & 8 Bit Immediate & Register \\ + 100 & 32 Bit Immediate & Register \\ + \hline + \end{tabularx} + \caption{Operand Mode Bit Pattern} + \label{fig:OperandModeBitPattern} + \paragraph{Note} The \textit{Immediate} values could represent an address (if 8-bit, relative otherwise 32-bit values will represent absolute addresses) or a numeric constant. \end{figure} -\begin{figure}[!htb] - \begin{tikzpicture} - \draw (\minX, \minY) -- (\maxX, \minY); - \draw (\minX, \minY) -- (\minX, \maxY) node[above] {31}; %{$y$}; Note the $'s, those make something math stylized. - \draw (\maxX, \minY) -- (\maxX, \maxY) node[above] {0}; - \draw (0, \minY) -- (0, \maxY) node[above] {15}; - \draw [decorate, decoration={brace, amplitude=1em, mirror}] (\minX, -\maxY) -- (0, -\maxY) node[midway, below=1em] {Op Code (16-bits)}; - \draw [decorate, decoration={brace, amplitude=1em, mirror}] (0, -\maxY) -- (\maxX, -\maxY) node[midway, below=1em] {Near Address (16-bits)}; - \end{tikzpicture} - \caption{Short Valued Opcodes} -\end{figure} - +\clearpage \section{Instructions} +The /r represents a byte that specifies a register. /iX is for the immediate data type, where \textit{X} defines the width, which are 8, 16, or 32 bits. \subsection{Add} -\OpcodeTable{01 /r /r}{add /r, /r}{Register}{Register} -\paragraph{Description} Sums \textit{Operand 1} and \textit{Operand 2} placing the result into \textit{Operand 1}. \ No newline at end of file +\OpcodeTable{01 /r /r}{add /r, /r}{Register}{Register}{Sums \textit{Operand 1} and \textit{Operand 2} placing the result into \textit{Operand 1}.} \ No newline at end of file