fixes for x86 abstract syntax

book.tex

@@ -2526,6 +2526,11 @@ programs, so we define an abstract syntax for x86 in
 Figure~\ref{fig:x86-int-ast}. We refer to this language as
 \LangXInt{}.
 %
+{\if\edition\pythonEd%
+  The main difference compared to the concrete syntax of \LangXInt{}
+  (Figure~\ref{fig:x86-int-concrete}) is that labels, instruction
+  names, and register names are explicitly represented by strings. 
+\fi} %
 {\if\edition\racketEd  
 The main difference compared to the concrete syntax of \LangXInt{}
 (Figure~\ref{fig:x86-int-concrete}) is that labels are not allowed in
@@ -2545,6 +2550,12 @@ node includes an integer for representing the arity of the function,
 i.e., the number of arguments, which is helpful to know during
 register allocation (Chapter~\ref{ch:register-allocation-Lvar}).
 
+\newcommand{\allastregisters}{\skey{rsp} \MID \skey{rbp} \MID \skey{rax} \MID \skey{rbx} \MID \skey{rcx}
+              \MID \skey{rdx} \MID \skey{rsi} \MID \skey{rdi} \MID \\
+              && \skey{r8} \MID \skey{r9} \MID \skey{r10}
+              \MID \skey{r11} \MID \skey{r12} \MID \skey{r13}
+              \MID \skey{r14} \MID \skey{r15}}
+
 \begin{figure}[tp]
 \fbox{
 \begin{minipage}{0.98\textwidth}
@@ -2569,15 +2580,15 @@ register allocation (Chapter~\ref{ch:register-allocation-Lvar}).
 {\if\edition\pythonEd
 \[
 \begin{array}{lcl}
-\Reg &::=& \allregisters{} \\
+\Reg &::=& \allastregisters{} \\
 \Arg &::=&  \IMM{\Int} \MID \REG{\Reg}
    \MID \DEREF{\Reg}{\Int} \\
-\Instr &::=& \BININSTR{\code{addq}}{\Arg}{\Arg} 
-       \MID \BININSTR{\code{subq}}{\Arg}{\Arg} \\
-       &\MID& \BININSTR{\code{movq}}{\Arg}{\Arg}
-       \MID \UNIINSTR{\code{negq}}{\Arg}\\
-       &\MID& \PUSHQ{\Arg} \MID \POPQ{\Arg}\\
-       &\MID& \CALLQ{\itm{label}}{\itm{int}} \MID \RETQ{} \MID \JMP{\itm{label}} \\
+\Instr &::=& \BININSTR{\scode{addq}}{\Arg}{\Arg} 
+       \MID \BININSTR{\scode{subq}}{\Arg}{\Arg} \\
+       &\MID& \BININSTR{\scode{movq}}{\Arg}{\Arg}
+       \MID \UNIINSTR{\scode{negq}}{\Arg}\\
+       &\MID&  \PUSHQ{\Arg} \MID \POPQ{\Arg} \\
+       &\MID& \CALLQ{\itm{label}}{\itm{int}} \MID \RETQ{}  \MID \JMP{\itm{label}} \\
 \LangXIntM{} &::= & \XPROGRAM{}{\Instr^{*}}{}
 \end{array}
 \]
@@ -3565,6 +3576,13 @@ For $\SEQ{s}{t}$, you can translate the statement $s$ and tail $t$
 recursively and then append the resulting instructions.
 \fi}
 
+{\if\edition\pythonEd
+We recommend that you use the function \code{utils.label\_name()} to
+transform a string into an label argument suitably suitable for, e.g.,
+the target of the \code{callq} instruction. This practice makes your
+compiler portable across Linus and Mac OS X, which requires an underscore prefixed to
+all labels.
+\fi}
 \begin{exercise}
   \normalfont
 {\if\edition\racketEd

defs.tex

@@ -108,7 +108,9 @@
 \newcommand{\Var}{\itm{var}}
 \newcommand{\Op}{\itm{op}}
 \newcommand{\key}[1]{\texttt{#1}}
+\newcommand{\skey}[1]{\texttt{'#1'}}
 \newcommand{\code}[1]{\texttt{#1}}
+\newcommand{\scode}[1]{\texttt{'#1'}}
 
 \newcommand{\LP}{\key{(}}
 \newcommand{\RP}{\key{)}}
@@ -325,8 +327,8 @@
 \newcommand{\BININSTR}[3]{\key{Instr}\LP #1 \key{,} \LS #2 \key{,} #3 \RS \RP}
 \newcommand{\UNIINSTR}[2]{\key{Instr}\LP #1 \key{,} \LS #2 \RS \RP}
 \newcommand{\CALLQ}[2]{\key{Callq}\LP #1 \key{,} #2 \RP}
-\newcommand{\PUSHQ}[1]{\key{Instr}\LP \code{pushq} \key{,} \LS #1 \RS \RP}
-\newcommand{\POPQ}[1]{\key{Instr}\LP \code{popq} \key{,} \LS #1 \RS \RP}
+\newcommand{\PUSHQ}[1]{\key{Instr}\LP \scode{pushq} \key{,} \LS #1 \RS \RP}
+\newcommand{\POPQ}[1]{\key{Instr}\LP \scode{popq} \key{,} \LS #1 \RS \RP}
 \newcommand{\JMP}[1]{\key{Jump}\LP #1 \RP}
 \newcommand{\JMPIF}[2]{\key{JumpIf}\LP #1 \key{,} #2 \RP}
 \newcommand{\RETQ}{\key{Retq}\LP\RP}