#!/usr/bin/perl

sub sanehead {
  my $blocktype = shift;
  my $offset = shift;
  my $dlen = shift;
  my $count = shift;

  if ($blocktype > 0x300)   { return 0 };
  if ($offset    > 0x10000) { return 0 };
  if ($dlen      > 20000)   { return 0 };
  return 1;
}

if ($#ARGV < 0) {
  print "EM8300 microcode extractor\n";
  print "Written by Henrik Johansson 2000-04-10\n\n";
  print "Usage:\n\tmicrocode_extract.pl FILE [DESTDIR] [NAMEBASE]\n\n";
  print "FILE refers to the VXD file which comes with the Windows drivers
and is found in the Windows\\System folder. The file is usually called
rmquasar.vxd (H+) or enc2dev.vxd (Creative Labs). \n\n";
  print "DESTDIR is the dir where the microcode should be stored.\n\n";
  print "NAMEBASE is the prefix of the saved microcode files.\n\n";
}

open(VXD,"<$ARGV[0]");
undef $/;
$vxd = <VXD>;
close(VXD);

$path = $ARGV[1];
$namebase = $ARGV[2];
if (length($namebase) == 0) { $namebase = "microcode" };

$ucnt = 0;

for ($i = 0; $i < length($vxd); $i++) {
  if (unpack('v', substr($vxd, $i, 2)) == 2) {
    $savei = $i;
    $ok = 1;
    $blocktype = -1;
    $count = 0;
    while ($blocktype != 0) {
      ($blocktype, $offset, $dlen) = unpack('vVV', substr($vxd, $i, 11));

      if ($blocktype == 0) {
        last;
      }
      if (($blocktype == 2) && (($lastblocktype & 0xf00) == 0x200)) {
        $i--; last;
      }

      $dlen *= 2;
      if (!sanehead($blocktype, $offset, $dlen, $count)) {
	$ok = 0;
	last;
      }
      $i += 10 + $dlen;
      $lastblocktype = $blocktype;
      $count++;
    }
    $lastblocktype = -1;
    if ($ok && $count > 20) {
      $ucodelen =  $i - $savei;
      $filename = "$path/$namebase$ucnt.bin";
      open UCODE, ">$filename" or die("Can't open microcode file");
      print UCODE substr($vxd, $savei, $ucodelen);
      print pack('SII', (0, 0, 0));
      close UCODE;
      print "Found microcode block (length=$ucodelen), ";
      print "saving to $filename \n";
      $ucnt++;
    }
    else {
      $i = $savei;
    }
  }
}