Subversion Repositories mpeg2fpga

#!/usr/bin/perl

# code used to generate the state machine graph.
# input: verilog code
# output: gml graph
# use: mkgraph < vld.v > vld.gml
#
# Flow:
#     mkfsmgraph < vld.v > vld.gml
#     gml2udg vld.gml  > vld.graph
#     uDrawGraph vld.graph
#     Choose menu "Layout->Improve All"
#     Choose menu "View->Full Scale"
#     Choose menu "File->Print" (print to file vld.ps, fit to page, center graph on page)
#     ps2pdf vld.ps
#
# Algorithm:
#
#   /* next state logic */
#     always @*
#       casex (state)
#         STATE_1:           if (somecondition) next = STATE_2;
#                              else next = STATE_1;
#
#  - find comment /* next state logic */
#  - take first always block after this comment
#  - any word beginning with STATE_ is a fsm state
#  - if character following the state is a colon (:) the state is source of a transition
#  - if character following the state is a semicolon (;) the state is destination of a transition
#
#
$gmlgraph = 1; # "gml" format
$dotgraph = 0; # "dot" format

%nodes = ();
%edges = ();
$cnt = 1;

$fsmfound = 0;

# extract next state logic from verilog
while (<>) {
  chop;
  if ($_ =~ /next state logic/) { $fsmfound = 1; }
  if ($_ =~ /always \@/) { if ($fsmfound == 1) {$fsmfound = 2; } else {$fsmfound = 0; }}

  if ($fsmfound) { $fsm = $fsm.$_; }
  }

# extract fsm states and edges from next state logic
while ($fsm =~ m/STATE_\w+/g) {
  $state = $&;

  if (!exists($nodes{$state})) {
    $nodes{$state} = $cnt;
    $cnt++;
    }

  $fsm =~ m/[:;]/g;
  $separator = $&;

  if ($separator eq ":") {
    $from = $state;
    }
  if ($separator eq ";") {
    $to = $state;
    $edges{"$from $to"} = 1;
    }
  }

if ($gmlgraph) {
  # output "gml" format graph 
  print "graph [\n";
  print " directed 1\n";
  
  foreach $key (sort keys %nodes) {
    print " node [ id ".$nodes{$key}." label \"".$key."\" ]\n";
    }
  
  foreach $key (sort keys %edges) {
    ($from, $to) = split (/ /, $key);
    # uncomment next two lines to simplify graph
    # next if ($to eq "STATE_NEXT_START_CODE");
    # next if ($to eq "STATE_ERROR");
    print " edge [ source ".$nodes{$from}." target ". $nodes{$to}." ] \n";
    }
  
  print "]\n"
  }

if ($dotgraph) {
  # output "dot" format graph
  print "digraph \"fsmgraph\" {\n";
  foreach $key (sort keys %edges) {
    ($from, $to) = split (/ /, $key);
    # uncomment next two lines to simplify graph
    # next if ($to eq "STATE_NEXT_START_CODE");
    # next if ($to eq "STATE_ERROR");
    print " \"".$from."\" -> \"".$to."\"\n";
    }
  print "}\n";
  }

# not truncated