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@@ -1055,7 +1055,7 @@ An x86 program is a sequence of instructions. The program is stored in the
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computer's memory and the \emph{program counter} points to the address of the
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next instruction to be executed. For most instructions, once the instruction is
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executed, the program counter is incremented to point to the immediately
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-following instruction in the program. Each instruction may refer to integer
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+following instruction in memory. Each instruction may refer to integer
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constants (called \emph{immediate values}), variables called \emph{registers},
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and instructions may load and store values into memory. For our purposes, we
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can think of the computer's memory as a mapping of 64-bit addresses to 64-bit
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@@ -1063,14 +1063,14 @@ can think of the computer's memory as a mapping of 64-bit addresses to 64-bit
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values\footnote{This simple story doesn't fully cover contemporary x86
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processors, which combine multiple processing cores per silicon chip, together
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with hardware memory caches. The result is that, at some instants in real
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- time, different programs may hold conflicting cached values for a given memory
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- address.}.
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+ time, different threads of program execution may hold conflicting
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+ cached values for a given memory address.}.
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%
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Figure~\ref{fig:x86-a} defines the syntax for the
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subset of the x86 assembly language needed for this chapter.
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%
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(We use the AT\&T syntax expected by the GNU assembler that comes with the C
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-compiler we use for this course: \key{gcc}.)
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+compiler that we use in this course: \key{gcc}.)
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%
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Also, Appendix~\ref{sec:x86-quick-reference} includes a quick-reference of all
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the x86 instructions used in this book and a short explanation of what they do.
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@@ -1114,7 +1114,8 @@ A register is written with a \key{\%} followed by the register name,
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such as \key{\%rax}.
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%
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An access to memory is specified using the syntax $n(\key{\%}r)$,
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-which reads register $r$ and then offsets the address by $n$ bytes
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+which obtains the address stored in register $r$ and then
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+offsets the address by $n$ bytes
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(8 bits). The address is then used to either load or store to memory
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depending on whether it occurs as a source or destination argument of
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an instruction.
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Jeremy Siek