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

#

# This one is used for simplifying the vld graph.

# Removes transitions to STATE_ERROR

# Removes transitions to STATE_NEXT_START_CODE; nodes are drawn with double border instead.

#

# Flow:

# 1. mkfsmgraph-vld < vld.v > vld-simple.gml

# 2. gml2udg vld-simple.gml  > vld-simple-1.graph

# 3. sed -e 's/"_GO","ellipse"/"BORDER","double"/g' < vld-simple-1.graph > vld-simple.graph

# 4. uDrawgraph vld-simple.graph

# 5. Choose menu "Layout -> Improve All"

# 6. Choose menu "View->Full Scale"

# 7. Choose menu "File->Print" (print to file vld-simple.ps, fit to page, center graph on page)

# 8. ps2pdf vld-simple.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) {

    if (!exists($edges{"$key STATE_NEXT_START_CODE"})) {

      print " node [ id ".$nodes{$key}." label \"".$key."\" ]\n";

      }

    else {

      print " node [ id ".$nodes{$key}." label \"".$key."\" graphics [ type \"ellipse\" ] ]\n";

      }

    }

  foreach $key (sort keys %edges) {

    ($from, $to) = split (/ /, $key);

    # uncomment next two lines to simplify vld graph

    next if (($to eq "STATE_NEXT_START_CODE") && ($from ne "STATE_ERROR"));

    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