1 files changed, 49 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/util/swapdevids.pl b/contrib/syslinux-4.02/gpxe/src/util/swapdevids.pl
new file mode 100755
index 0000000..c6255ae
--- /dev/null
+++ b/contrib/syslinux-4.02/gpxe/src/util/swapdevids.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/perl -w
+#
+#	Program to reverse the device identifier IDs in the PCIR and PnP
+#	structures in a ROM for old non-compliant BIOSes
+#
+#	GPL, Ken Yap 2001
+#
+
+use bytes;
+
+use IO::Seekable;
+
+sub swaplocs ($$$)
+{
+	my ($dataref, $loc1, $loc2) = @_;
+	my ($t);
+
+	$t = substr($$dataref, $loc1, 1);
+	substr($$dataref, $loc1, 1) = substr($$dataref, $loc2, 1);
+	substr($$dataref, $loc2, 1) = $t;
+}
+
+sub printdevids ($$)
+{
+	my ($dataref, $loc) = @_;
+
+	return (sprintf "%02x %02x %02x", unpack('C3', substr($$dataref, $loc, 3)));
+}
+
+$#ARGV >= 0 or die "Usage: $0 romimage\n";
+$file = $ARGV[0];
+open(F, "+<$file") or die "$file: $!\n";
+binmode(F);
+# Handle up to 64kB ROM images
+$len = read(F, $data, 64*1024);
+defined($len) or die "$file: $!\n";
+substr($data, 0, 2) eq "\x55\xAA" or die "$file: Not a boot ROM image\n";
+($pci, $pnp) = unpack('v2', substr($data, 0x18, 4));
+($pci < $len and $pnp < $len) or die "$file: Not a PCI PnP ROM image\n";
+(substr($data, $pci, 4) eq 'PCIR' and substr($data, $pnp, 4) eq '$PnP')
+	or die "$file: No PCI and PNP structures, not a PCI PNP ROM image\n";
+&swaplocs(\$data, $pci+13, $pci+15);
+&swaplocs(\$data, $pnp+18, $pnp+20);
+seek(F, 0, SEEK_SET) or die "$file: Cannot seek to beginning\n";
+print F $data;
+close(F);
+print "PCI devids now: ", &printdevids(\$data, $pci+13), "\n";
+print "PnP devids now: ", &printdevids(\$data, $pnp+18), "\n";
+exit(0);