diff --git a/tools/checker.pl b/tools/checker.pl
new file mode 100755
index 0000000..c687cf9
--- /dev/null
+++ b/tools/checker.pl
@@ -0,0 +1,100 @@
+#!/usr/pkg/bin/perl
+#
+# Checker script - checks if a bunch of macro11 object files have
+# undefined symbols left over.
+#
+# Uses the dumpobj tool to parse the object files.
+#
+use strict;
+#use Data::Dumper;
+
+my %symtab;
+
+# Symbols are stored in the symbol table.
+# They have 2 fields:
+# - a list of definitions (hopefully 1 entry long)
+# - a list of references
+
+sub read_object_file {
+    my $fn = shift;
+
+    if ($fn =~ /\.def$/i) {
+	open OBJ, "<", $fn;
+    } else {
+	open OBJ, "dumpobj '".$fn."' |";
+    }
+
+    my $gsd = 0;
+    my $line = <OBJ>;
+
+    while (defined $line) {
+	# print $line;
+	if ($line =~ /^GSD:/) {
+	    $gsd = 1;
+	    # print "gsd = 1\n";
+	} elsif ($line =~ /^ENDGSD/) {
+	    $gsd = 0;
+	    # print "gsd = 0\n";
+	} elsif ($gsd) {
+	    #print $line;
+	    #  GLOBAL AT$CDT=0 REF ABS flags=100
+	    if ($line =~ /GLOBAL ([A-Z0-9.\$]*)=[0-9]* (.*)/) {
+		my $symbol = $1;
+		my $flags = $2;
+
+		#print "flags: $flags\n";
+		my $key = 'refs';
+		if ($flags =~ /\bDEF\b/) {
+		    $key = 'defs';
+		}
+
+		if (!defined $symtab{$symbol}) {
+		     $symtab{$symbol} = {
+			 'defs' => [],
+			 'refs' => []
+		     };
+		}
+
+		push @{$symtab{$symbol}->{$key}}, $fn;
+	    }
+	}
+	$line = <OBJ>;
+    }
+
+    close OBJ;
+}
+
+# Read all object files
+
+foreach my $fn (@ARGV) {
+    read_object_file($fn);
+
+    # print Dumper(\%symtab);
+}
+
+# Check which symbols have no definition
+
+print "Symbols with no definition:\n";
+my $undefs = 0;
+
+foreach my $key (sort keys %symtab) {
+    #print $key, " : ", Dumper($entry);
+    my $entry = %symtab{$key};
+
+    my @defs = @{$entry->{defs}};
+    #print (@defs), "\n";
+    #print scalar(@defs), "\n";
+
+    if (scalar(@defs) == 0) {
+	$undefs++;
+	print $key, ":";
+	for my $ref (@{$entry->{refs}}) {
+	    print " ", $ref;
+	}
+	print "\n";
+    }
+}
+
+if ($undefs == 0) {
+    print "(none)\n";
+}