Verilog Translator

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Getting Started » History » Revision 3

Revision 2 (Alexander Kamkin, 05/05/2014 02:52 PM) → Revision 3/11 (Alexander Kamkin, 05/06/2014 07:58 AM)

h1. Getting Started 

 This is a step-by-step instruction for getting started with developing a VeriTrans backend and using it within the Verilog translator environment. The term _backend_ refers to a component that traverses an _abstract syntax tree_ (_AST_) of the Verilog description and processes it in some way (e.g., constructs the internal representation and/or converts the description into some other language). The document is illustrated by the example of @VerilogPrinter@ (see the package @ru.ispras.verilog.parser.sample@). 

 h2. Developing a Backend 

 Technically, a backend is a Java object that implements the @VerilogBackend@ interface (the method @start@). Here is an example: 

 <pre><code class="java"> 
 package ru.ispras.verilog.parser.sample; 

 import ru.ispras.verilog.parser.VerilogBackend; 
 import ru.ispras.verilog.parser.model.*; 
 ... import ru.ispras.verilog.parser.walker.*; 

 /** 
  * This class illustrates development of a Verilog backend. back-end. 
  * 
  * @author <a href="mailto:kamkin@ispras.ru">Alexander Kamkin</a> 
  */ 
 public final class VerilogPrinter extends VerilogBackend 
 { 
     /** 
      * Processes the abstract syntax tree (AST). {@inheritDoc} 
      * 
      * @param root the AST''s root. 
      */ 
     @Override 
     public void start(final VerilogNode root) 
     { 
         ... 
     } 
 } 
 </code></pre> 

 To ease development of a backend, one can use @VerilogTreeWalker@, a VeriTrans class that implements AST traversal. The @VerilogTreeWalker@''s constructor takes two parameters: (1) a reference to the tree''s root and (2) a visitor to be applied to the tree nodes: 

 <pre><code class="java"> 
 import ru.ispras.verilog.parser.walker.*; 

 public void start(final VerilogNode root) 
 { 
     VerilogTreeWalker walker = new VerilogTreeWalker(root, new VerilogNodePrinter()); 
         walker.start(); 
     walker.start(); } 
 } 
 </code></pre> 

 h2. Registering a Backend