Loading acronym.tex 0 → 100644 +14 −0 Original line number Diff line number Diff line \newacronym{bcd}{BCD}{binary coded decimal} \newacronym{acr-cli}{CLI}{command line interface} \newacronym{fpu}{FPU}{floating point unit} \newacronym{gdb}{GDB}{GNU Debugger} \newacronym{os}{OS}{operating system} \newacronym{tlb}{TLB}{translation lookaside buffer} \newacronym{vm}{VM}{virtual machine} glossary.tex 0 → 100644 +40 −0 Original line number Diff line number Diff line \newglossaryentry{debian}{ name=debian, description={the Linux distribution used in this book} } \newglossaryentry{debugger}{ name=debugger, description={a program to execute and monitor another program and stop the execution of the monitored program for examination} } \newglossaryentry{git}{ name=git, description={a version control system} } \newglossaryentry{linux}{ name=Linux, description={an operating system} } \newglossaryentry{nasm}{ name=NASM, description={the assembler used in this book (The Netwide Assembler)} } \newglossaryentry{qemu}{ name=QEMU, description={the \gls{x86} emulator used in this book} } \newglossaryentry{x86}{ name=x86, description={a microprocessor architecture based on the 8086/8088 from Intel} } \newglossaryentry{x87}{ name=x87, description={a mathematical coprocessor for the \gls{x86}} } ins-gls.tex +1 −1 Original line number Diff line number Diff line Loading @@ -1238,7 +1238,7 @@ \newglossaryentry{cpuid}{ type=ins-glo, name=\texttt{CPUID}, description={CPU identification, introduced with \nameref{ch:CPUID}} description={CPU identification, introduced with \nameref{ch:cpuid}} } \newglossaryentry{cmpxchg8b}{ Loading tutorial.nw +219 −45 Original line number Diff line number Diff line Loading @@ -50,45 +50,9 @@ \setacronymstyle{long-short} \newacronym{bcd}{BCD}{binary coded decimal} \loadglsentries{acronym} \newacronym{fpu}{FPU}{floating point unit} \newacronym{gdb}{GDB}{GNU Debugger} \newacronym{tlb}{TLB}{translation lookaside buffer} \newacronym{vm}{VM}{virtual machine} \newglossaryentry{git}{ name=git, description={a version control system} } \newglossaryentry{nasm}{ name=NASM, description={the assembler used in this book (The Netwide Assembler)} } \newglossaryentry{qemu}{ name=QEMU, description={the \gls{x86} emulator used in this book} } \newglossaryentry{debian}{ name=debian, description={the Linux distribution used in this book} } \newglossaryentry{x86}{ name=x86, description={a microprocessor architecture based on the 8086/8088 from Intel} } \newglossaryentry{x87}{ name=x87, description={a mathematical coprocessor for the \gls{x86}} } \loadglsentries{glossary} \loadglsentries{ins-gls} Loading Loading @@ -127,7 +91,7 @@ language extensions in chapter \ref{ch:8087}, which is the first \gls{x87} \gls{ Further on I will visit the other CPUs in historical order. We go on with the \nameref{ch:80286} in chapter \ref{ch:80286}, the \nameref{ch:80386} in chapter \ref{ch:80386} and the \nameref{ch:80486} in chapter \ref{ch:80486}. After that I will not go on with different processors but with features. This starts with the chapter \nameref{ch:CPUID} After that I will not go on with different processors but with features. This starts with the chapter \nameref{ch:cpuid} which is the first feature I'll discuss. This is the base for all other features because with the \gls{cpuid} you can determine all other features. This is because not every processor needs to implement all features. Loading Loading @@ -162,12 +126,45 @@ Additionally this book has several appendices. The appendices have the following When an instruction is used on a page this instruction in printed in the margin for easier reference. \section{Environment} All examples in this book are written in Intel syntax. To see the differences between AT\&T syntax and Intel syntax please refer to the chapter \ref{ch:Assembly Syntax}~\nameref{ch:Assembly Syntax}. In examples I will write the instructions in lower case letters and registers in upper case letters. If I need to use a label then this will also be in lower case. \chapter{Environment} \section{Introduction} To develop software, independent of the programming language used, you need some tools. I selected some tools that I will use in this tutorial. We will not develop application software in this tutorial but will look at the instructions and therefore have special requirements on the tools. Also we have nothing that supports us with doing regular tasks such as printing a text to the screen. Therefore most of the time we will run our programs in an isolated environment and see the results directly in a \gls{debugger}. \subsection{Setup} If you are used to work with \gls{linux}\index{Linux} then please go on to section \ref{sec:environment/setup}. There I list all software needed and give a short introduction to each of this tools. Developing in assembly is sometimes cumbersome because you have not much help of the tools, e.g. the assembler does not do many checks for you. If you do not know \gls{linux}\index{Linux} or are not used to work with the \gls{acr-cli} then it is best to continue with section \ref{sec:environment/vm}. In this section I will show a \gls{vm}\index{VM} that contains everything and also give an instruction on how to use everything with a step--by--step introduction. \section{Setup} \label{sec:environment/setup} Needed software: \begin{itemize} \item \gls{nasm} \item \gls{gdb} \item \gls{qemu} (install the package qemu-system-x86) \item \gls{git} \end{itemize} \section{VM} \label{sec:environment/vm} So to help you with using this tutorial I created a toolset that may help you. Basically I created a \gls{vm} that contains everything that you need to see the instructions work as explained in this book. The \gls{vm} contains a basic Loading Loading @@ -250,7 +247,7 @@ target remote localhost:1234 This file sets the correct breakpoint and program layout for \gls{gdb} and tries to connect to \gls{qemu} which should already be running when calling \gls{gdb}. \subsection{Test Setup} \section{Test Setup} Loading Loading @@ -982,7 +979,7 @@ TBD\marginnote{\gls{xadd}} TBD\marginnote{\gls{rsm}} \chapter{Processor with CPUID} \label{ch:CPUID} \label{ch:cpuid} \begin{itemize} \item released 1993 (Intel) Loading Loading @@ -1382,6 +1379,183 @@ This is a temporary chapter to help me organize this book. \appendix \chapter{Assembly Syntax} \label{ch:Assembly Syntax} \section{Introduction} There are two different syntaxes for assembly language for the \gls{x86} assembly language. One is the AT\&T\index[idx]{Assembly Syntax!AT\&T} syntax and the other is the Intel\index[idx]{Assembly Syntax!Intel} syntax. The difference looks like this:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movw %DX,%AX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AX,DX \end{Verbatim} \end{minipage} \vspace{1ex} If you work with \gls{linux} or other Unix like systems you will most likely find the AT\&T syntax. If you use material from Intel you will find the Intel syntax. I will use the Intel syntax in this book as I will reference Intel material for reference. In the remaining section I will explain all differences between the syntaxes. \section{Register Naming} The registers have a plain name in Intel, like \verb|AX| or \verb|RAX|. In AT\&T syntax each register is prefixed with \verb|%| so the registers would be named \verb|%AX| or \verb|%RAX|. Example:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] %AX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] AX \end{Verbatim} \end{minipage} \vspace{1ex} \section{Immediate Value} If you use an immediate value (e.g. a constant) then you have to prefix this with \verb|$| in AT\&T syntax. In Intel syntax a prefix is not needed. When using binary immediates you have to prefix the value with \verb|0b|, hexadecimal immediates must be prefixed with \verb|0x|. If you start an immediate with \verb|0| (the figure 0) then the value is interpreted as octal in AT\&T syntax whereas in Intel syntax you prefix the immediate with \verb|0o| or \verb|0q|. Example for moving a binary value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0b00111100,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0b00111100 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving an octal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0123,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0o123 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving a decimal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $15,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,15 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving a hexadecimal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0xab,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0xab \end{Verbatim} \end{minipage} \vspace{1ex} \section{Order of Operands} The order of operands are reversed between AT\&T syntax and Intel syntax. In AT\&T syntax you name the source operand(s) first and the target last. In Intel syntax the target is named first and then the source operand(s). Example to move a value from \verb|AX| to \verb|BX|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movl %AX,%BX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BX,AX \end{Verbatim} \end{minipage} \vspace{1ex} \section{Data Size Determination} In AT\&T syntax you usually append a suffix to the instruction to determine the data size. This is done by appending \verb|b| for byte (8~bit integer) operands, \verb|s| for short (16~bit integer/32~bit float) operands, \verb|w| for word (16~bit integer) operands, \verb|l| for long (32~bit integer/64~bit float) operands, \verb|q| for quad (64~bit integer) operands and \verb|t| for ten~byte (80~bit float) operands. In Intel sytax you only determine the operand size if it is not deferable by the operands directly. So you add \verb|byte| for a byte (8~bit), \verb|word| for a word (16~bit), \verb|dword| for a double word (32~bit) and \verb|qword| for a quad word (64~bit). Example to move a byte to a register:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0x80,%AL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AL,0x80 \end{Verbatim} \end{minipage} \vspace{1ex} Example to move a word into a memory location:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movw $0x8080,(%EAX) \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov word[EAX],0x8080 \end{Verbatim} \end{minipage} \vspace{1ex} \section{Indirect Memory Access} When accessing the memory with an address in a register the syntax also differs. In AT\&T syntax you enclose the register with round brackets (\verb|()|). In Intel syntax you use square brackets for this (\verb|[]|). Example to load the byte from the address stored in \verb|ESI| to \verb|AH|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb (%ESI),%AH \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AH,[ESI] \end{Verbatim} \end{minipage} \vspace{1ex} \printglossary \printacronyms Loading tutorial.pdf +2 −2 Original line number Diff line number Diff line version https://git-lfs.github.com/spec/v1 oid sha256:a94ee5bb7119990761dc04b3e6e64e008b8e5f050b8081a7da641d2d7b053b80 size 180658 oid sha256:f31dbc40f88f9aa1f0ca3d6d812393eec8f1788f632dfa3040ae7749752c2aa4 size 192720 Loading
acronym.tex 0 → 100644 +14 −0 Original line number Diff line number Diff line \newacronym{bcd}{BCD}{binary coded decimal} \newacronym{acr-cli}{CLI}{command line interface} \newacronym{fpu}{FPU}{floating point unit} \newacronym{gdb}{GDB}{GNU Debugger} \newacronym{os}{OS}{operating system} \newacronym{tlb}{TLB}{translation lookaside buffer} \newacronym{vm}{VM}{virtual machine}
glossary.tex 0 → 100644 +40 −0 Original line number Diff line number Diff line \newglossaryentry{debian}{ name=debian, description={the Linux distribution used in this book} } \newglossaryentry{debugger}{ name=debugger, description={a program to execute and monitor another program and stop the execution of the monitored program for examination} } \newglossaryentry{git}{ name=git, description={a version control system} } \newglossaryentry{linux}{ name=Linux, description={an operating system} } \newglossaryentry{nasm}{ name=NASM, description={the assembler used in this book (The Netwide Assembler)} } \newglossaryentry{qemu}{ name=QEMU, description={the \gls{x86} emulator used in this book} } \newglossaryentry{x86}{ name=x86, description={a microprocessor architecture based on the 8086/8088 from Intel} } \newglossaryentry{x87}{ name=x87, description={a mathematical coprocessor for the \gls{x86}} }
ins-gls.tex +1 −1 Original line number Diff line number Diff line Loading @@ -1238,7 +1238,7 @@ \newglossaryentry{cpuid}{ type=ins-glo, name=\texttt{CPUID}, description={CPU identification, introduced with \nameref{ch:CPUID}} description={CPU identification, introduced with \nameref{ch:cpuid}} } \newglossaryentry{cmpxchg8b}{ Loading
tutorial.nw +219 −45 Original line number Diff line number Diff line Loading @@ -50,45 +50,9 @@ \setacronymstyle{long-short} \newacronym{bcd}{BCD}{binary coded decimal} \loadglsentries{acronym} \newacronym{fpu}{FPU}{floating point unit} \newacronym{gdb}{GDB}{GNU Debugger} \newacronym{tlb}{TLB}{translation lookaside buffer} \newacronym{vm}{VM}{virtual machine} \newglossaryentry{git}{ name=git, description={a version control system} } \newglossaryentry{nasm}{ name=NASM, description={the assembler used in this book (The Netwide Assembler)} } \newglossaryentry{qemu}{ name=QEMU, description={the \gls{x86} emulator used in this book} } \newglossaryentry{debian}{ name=debian, description={the Linux distribution used in this book} } \newglossaryentry{x86}{ name=x86, description={a microprocessor architecture based on the 8086/8088 from Intel} } \newglossaryentry{x87}{ name=x87, description={a mathematical coprocessor for the \gls{x86}} } \loadglsentries{glossary} \loadglsentries{ins-gls} Loading Loading @@ -127,7 +91,7 @@ language extensions in chapter \ref{ch:8087}, which is the first \gls{x87} \gls{ Further on I will visit the other CPUs in historical order. We go on with the \nameref{ch:80286} in chapter \ref{ch:80286}, the \nameref{ch:80386} in chapter \ref{ch:80386} and the \nameref{ch:80486} in chapter \ref{ch:80486}. After that I will not go on with different processors but with features. This starts with the chapter \nameref{ch:CPUID} After that I will not go on with different processors but with features. This starts with the chapter \nameref{ch:cpuid} which is the first feature I'll discuss. This is the base for all other features because with the \gls{cpuid} you can determine all other features. This is because not every processor needs to implement all features. Loading Loading @@ -162,12 +126,45 @@ Additionally this book has several appendices. The appendices have the following When an instruction is used on a page this instruction in printed in the margin for easier reference. \section{Environment} All examples in this book are written in Intel syntax. To see the differences between AT\&T syntax and Intel syntax please refer to the chapter \ref{ch:Assembly Syntax}~\nameref{ch:Assembly Syntax}. In examples I will write the instructions in lower case letters and registers in upper case letters. If I need to use a label then this will also be in lower case. \chapter{Environment} \section{Introduction} To develop software, independent of the programming language used, you need some tools. I selected some tools that I will use in this tutorial. We will not develop application software in this tutorial but will look at the instructions and therefore have special requirements on the tools. Also we have nothing that supports us with doing regular tasks such as printing a text to the screen. Therefore most of the time we will run our programs in an isolated environment and see the results directly in a \gls{debugger}. \subsection{Setup} If you are used to work with \gls{linux}\index{Linux} then please go on to section \ref{sec:environment/setup}. There I list all software needed and give a short introduction to each of this tools. Developing in assembly is sometimes cumbersome because you have not much help of the tools, e.g. the assembler does not do many checks for you. If you do not know \gls{linux}\index{Linux} or are not used to work with the \gls{acr-cli} then it is best to continue with section \ref{sec:environment/vm}. In this section I will show a \gls{vm}\index{VM} that contains everything and also give an instruction on how to use everything with a step--by--step introduction. \section{Setup} \label{sec:environment/setup} Needed software: \begin{itemize} \item \gls{nasm} \item \gls{gdb} \item \gls{qemu} (install the package qemu-system-x86) \item \gls{git} \end{itemize} \section{VM} \label{sec:environment/vm} So to help you with using this tutorial I created a toolset that may help you. Basically I created a \gls{vm} that contains everything that you need to see the instructions work as explained in this book. The \gls{vm} contains a basic Loading Loading @@ -250,7 +247,7 @@ target remote localhost:1234 This file sets the correct breakpoint and program layout for \gls{gdb} and tries to connect to \gls{qemu} which should already be running when calling \gls{gdb}. \subsection{Test Setup} \section{Test Setup} Loading Loading @@ -982,7 +979,7 @@ TBD\marginnote{\gls{xadd}} TBD\marginnote{\gls{rsm}} \chapter{Processor with CPUID} \label{ch:CPUID} \label{ch:cpuid} \begin{itemize} \item released 1993 (Intel) Loading Loading @@ -1382,6 +1379,183 @@ This is a temporary chapter to help me organize this book. \appendix \chapter{Assembly Syntax} \label{ch:Assembly Syntax} \section{Introduction} There are two different syntaxes for assembly language for the \gls{x86} assembly language. One is the AT\&T\index[idx]{Assembly Syntax!AT\&T} syntax and the other is the Intel\index[idx]{Assembly Syntax!Intel} syntax. The difference looks like this:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movw %DX,%AX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AX,DX \end{Verbatim} \end{minipage} \vspace{1ex} If you work with \gls{linux} or other Unix like systems you will most likely find the AT\&T syntax. If you use material from Intel you will find the Intel syntax. I will use the Intel syntax in this book as I will reference Intel material for reference. In the remaining section I will explain all differences between the syntaxes. \section{Register Naming} The registers have a plain name in Intel, like \verb|AX| or \verb|RAX|. In AT\&T syntax each register is prefixed with \verb|%| so the registers would be named \verb|%AX| or \verb|%RAX|. Example:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] %AX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] AX \end{Verbatim} \end{minipage} \vspace{1ex} \section{Immediate Value} If you use an immediate value (e.g. a constant) then you have to prefix this with \verb|$| in AT\&T syntax. In Intel syntax a prefix is not needed. When using binary immediates you have to prefix the value with \verb|0b|, hexadecimal immediates must be prefixed with \verb|0x|. If you start an immediate with \verb|0| (the figure 0) then the value is interpreted as octal in AT\&T syntax whereas in Intel syntax you prefix the immediate with \verb|0o| or \verb|0q|. Example for moving a binary value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0b00111100,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0b00111100 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving an octal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0123,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0o123 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving a decimal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $15,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,15 \end{Verbatim} \end{minipage} \vspace{1ex} Example for moving a hexadecimal value to \verb|BL|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0xab,%BL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BL,0xab \end{Verbatim} \end{minipage} \vspace{1ex} \section{Order of Operands} The order of operands are reversed between AT\&T syntax and Intel syntax. In AT\&T syntax you name the source operand(s) first and the target last. In Intel syntax the target is named first and then the source operand(s). Example to move a value from \verb|AX| to \verb|BX|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movl %AX,%BX \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov BX,AX \end{Verbatim} \end{minipage} \vspace{1ex} \section{Data Size Determination} In AT\&T syntax you usually append a suffix to the instruction to determine the data size. This is done by appending \verb|b| for byte (8~bit integer) operands, \verb|s| for short (16~bit integer/32~bit float) operands, \verb|w| for word (16~bit integer) operands, \verb|l| for long (32~bit integer/64~bit float) operands, \verb|q| for quad (64~bit integer) operands and \verb|t| for ten~byte (80~bit float) operands. In Intel sytax you only determine the operand size if it is not deferable by the operands directly. So you add \verb|byte| for a byte (8~bit), \verb|word| for a word (16~bit), \verb|dword| for a double word (32~bit) and \verb|qword| for a quad word (64~bit). Example to move a byte to a register:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb $0x80,%AL \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AL,0x80 \end{Verbatim} \end{minipage} \vspace{1ex} Example to move a word into a memory location:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movw $0x8080,(%EAX) \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov word[EAX],0x8080 \end{Verbatim} \end{minipage} \vspace{1ex} \section{Indirect Memory Access} When accessing the memory with an address in a register the syntax also differs. In AT\&T syntax you enclose the register with round brackets (\verb|()|). In Intel syntax you use square brackets for this (\verb|[]|). Example to load the byte from the address stored in \verb|ESI| to \verb|AH|:\\ \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=AT\&T Syntax] movb (%ESI),%AH \end{Verbatim} \end{minipage} \begin{minipage}[t]{0.5\textwidth} \begin{Verbatim}[frame=single,label=Intel Syntax] mov AH,[ESI] \end{Verbatim} \end{minipage} \vspace{1ex} \printglossary \printacronyms Loading
tutorial.pdf +2 −2 Original line number Diff line number Diff line version https://git-lfs.github.com/spec/v1 oid sha256:a94ee5bb7119990761dc04b3e6e64e008b8e5f050b8081a7da641d2d7b053b80 size 180658 oid sha256:f31dbc40f88f9aa1f0ca3d6d812393eec8f1788f632dfa3040ae7749752c2aa4 size 192720
