
diff -r b7c526b01931 -r 0b707b614dac handouts/ho07.tex
--- a/handouts/ho07.tex	Sat Oct 15 14:27:01 2016 +0100
+++ b/handouts/ho07.tex	Mon Oct 17 13:18:34 2016 +0100
@@ -17,15 +17,33 @@
 the fastest possible code, but code that is fast enough and
 has the advantage that the virtual machine takes care of
 things a compiler would normally need to take care of (like
-explicit memory management).
+explicit memory management). Why study compilers? John Regher
+gives this answer in his compiler blog:\footnote{\url{http://blog.regehr.org/archives/1419}}
 
-As a first example we will implement a compiler for the very
-simple While-language. It will generate code for the Java
-Virtual Machine (JVM). This is a stack-based virtual machine,
-a fact which will make it easy to generate code for arithmetic
-expressions. For example for generating code for the
-expression $1 + 2$ we need to generate the following three
-instructions
+\begin{quote}\it{}``We can start off with a couple of observations
+  about the role of compilers. First, hardware is getting weirder
+  rather than getting clocked faster: almost all processors are
+  multicores and it looks like there is increasing asymmetry in
+  resources across cores. Processors come with vector units, crypto
+  accelerators, bit twiddling instructions, and lots of features to
+  make virtualization and concurrency work. We have DSPs, GPUs,
+  big.little, and Xeon Phi. This is only scratching the
+  surface. Second, we’re getting tired of low-level languages and
+  their associated security disasters, we want to write new code, to
+  whatever extent possible, in safer, higher-level
+  languages. Compilers are caught right in the middle of these
+  opposing trends: one of their main jobs is to help bridge the large
+  and growing gap between increasingly high-level languages and
+  increasingly wacky platforms. It’s effectively a perpetual
+  employment act for solid compiler hackers.''
+\end{quote}  
+
+As a first example in this module we will implement a compiler for the
+very simple While-language. It will generate code for the Java Virtual
+Machine (JVM). This is a stack-based virtual machine, a fact which
+will make it easy to generate code for arithmetic expressions. For
+example for generating code for the expression $1 + 2$ we need to
+generate the following three instructions
 
 \begin{lstlisting}[numbers=none]
 ldc 1




