glm94/lang
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Updated the Encoding Scheme section adding a 'operand mode' setting to the encoding as well changing the placement of the figures in that section.

Browse Source
This commit is contained in:
Garritt McCune
2024-07-19 13:50:44 -05:00
parent 5c646a4835
commit df15bb60e7
1 changed files with 49 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files
chapter 2.tex
+49 -26
View File
@@ -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}.
\OpcodeTable{01 /r /r}{add /r, /r}{Register}{Register}{Sums \textit{Operand 1} and \textit{Operand 2} placing the result into \textit{Operand 1}.}