Add image of the compiler pipeline and fix some spelling errors

[matthijs/master-project/dsd-paper.git] / cλash.lhs

diff --git a/cλash.lhs b/cλash.lhs
index c4a281f53f9d3e481545c29f745b401d9c30428e..b43aca82384bfb88c678106dc94b2f1ca7ee3bef 100644 (file)
--- a/cλash.lhs
+++ b/cλash.lhs
@@ -810,8 +810,8 @@ by an (optimizing) \VHDL\ synthesis tool.
         % value.
       \item[\bf{Multiple constructors with fields}]
         Algebraic datatypes with multiple constructors, where at least
         % value.
       \item[\bf{Multiple constructors with fields}]
         Algebraic datatypes with multiple constructors, where at least

-        one of these constructors has one or more fields are not
-        currently supported.
+        one of these constructors has one or more fields are currently not 
+        supported.

     \end{xlist}
 
   \subsection{Polymorphism}
     \end{xlist}
 
   \subsection{Polymorphism}


@@ -1013,7 +1013,32 @@ by an (optimizing) \VHDL\ synthesis tool.
     
 \section{\CLaSH\ prototype}
 
     
 \section{\CLaSH\ prototype}
 

-foo\par bar
+The \CLaSH\ language as presented above can be translated to \VHDL\ using
+the prototype \CLaSH\ compiler. This compiler allows experimentation with
+the \CLaSH\ language and allows for running \CLaSH\ designs on actual FPGA
+hardware.
+
+\begin{figure}
+\centerline{\includegraphics{compilerpipeline.svg}}
+\caption{\CLaSH\ compiler pipeline}
+\label{img:compilerpipeline}
+\end{figure}
+
+The prototype heavily uses \GHC, the Glasgow Haskell Compiler. 
+\Cref{img:compilerpipeline} shows the \CLaSH\ compiler pipeline. As you can 
+see, the front-end is completely reused from \GHC, which allows the \CLaSH\ 
+prototype to support most of the Haskell Language. The \GHC\ front-end 
+produces the program in the \emph{Core} format, which is a very small, 
+functional, typed language which is relatively easy to process.
+
+The second step in the compilation process is \emph{normalization}. This
+step runs a number of \emph{meaning preserving} transformations on the
+Core program, to bring it into a \emph{normal form}. This normal form
+has a number of restrictions that make the program similar to hardware.
+In particular, a program in normal form no longer has any polymorphism
+or higher order functions.
+
+The final step is a simple translation to \VHDL.

 
 \section{Use cases}
 As an example of a common hardware design where the use of higher-order
 
 \section{Use cases}
 As an example of a common hardware design where the use of higher-order


@@ -1126,7 +1151,7 @@ synchronous and untimed models of computation. Using so-called domain
 interfaces a designer can simulate electronic systems which have both analog 
 as digital parts. ForSyDe has several simulation and  synthesis backends, 
 though synthesis is restricted to the synchronous subset of the ForSyDe 
 interfaces a designer can simulate electronic systems which have both analog 
 as digital parts. ForSyDe has several simulation and  synthesis backends, 
 though synthesis is restricted to the synchronous subset of the ForSyDe 

-language. Unlike \CLaSH\ there is no support for the automated synthesis of description that contain polymorphism or higher-order functions.
+language. Unlike \CLaSH\ there is no support for the automated synthesis of descriptions that contain polymorphism or higher-order functions.

 
 Lava~\cite{Lava} is a hardware description language that focuses on the 
 structural representation of hardware. Besides support for simulation and 
 
 Lava~\cite{Lava} is a hardware description language that focuses on the 
 structural representation of hardware. Besides support for simulation and