edit regarding optimizing jumps

book.tex

@@ -4950,9 +4950,11 @@ each block in the program, updating the target of every \code{goto}
 according to the mapping in \code{short-cut}.
 
 \begin{exercise}\normalfont
-  Implement the \code{optimize-jumps} pass and check that it remove
-  trivial blocks in a few example programs. Then check that your
-  compiler still passes all of your tests.
+  Implement the \code{optimize-jumps} pass as a transformation from
+  $C_1$ to $C_1$, coming after the \code{explicate-control} pass.
+  Check that \code{optimize-jumps} removes trivial blocks in a few
+  example programs. Then check that your compiler still passes all of
+  your tests.
 \end{exercise}
 
 There is another opportunity for optimizing jumps that is apparent in
@@ -5008,7 +5010,10 @@ block7952:
 \begin{exercise}\normalfont
   Implement a pass named \code{remove-jumps} that merges basic blocks
   into their preceeding basic block, when there is only one preceeding
-  block. Check that your pass accomplishes this goal on several test
+  block. The pass should translate from psuedo $x86_1$ to pseudo
+  $x86_1$ and it should come immediately after
+  \code{select-instructions}.  Check that \code{remove-jumps}
+  accomplishes the goal of merging basic blocks on several test
   programs and check that your compiler passes all of your tests.
 \end{exercise}