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1#!/usr/bin/perl -w
2
3use warnings;
4use strict;
5
6use bytes;
7
8use constant MAX_ROM_LEN => 1024*1024;
9use constant PCI_OFF => 0x18;
10use constant INDICATOR_OFF => 0x15;
11
12my $total_len = 0;
13my @romfiles = @ARGV
14    or die "Usage: $0 rom-file-1 rom-file-2 ... > multi-rom-file\n";
15
16while ( my $romfile = shift @romfiles ) {
17  my $last = @romfiles ? 0 : 1;
18
19  open ROM, "<$romfile" or die "Could not open $romfile: $!\n";
20  my $len = read ( ROM, my $romdata, MAX_ROM_LEN )
21      or die "Could not read $romfile: $!\n";
22  close ROM;
23
24  die "$romfile is not a ROM file\n"
25      unless substr ( $romdata, 0, 2 ) eq "\x55\xAA";
26
27  ( my $checklen ) = unpack ( 'C', substr ( $romdata, 2, 1 ) );
28  $checklen *= 512;
29  die "$romfile has incorrect length field $checklen (should be $len)\n"
30      unless $len == $checklen;
31
32  ( my $pci ) = unpack ( 'v', substr ( $romdata, PCI_OFF, 2 ) );
33  die "Invalid PCI offset field in $romfile\n"
34      if $pci >= $len;
35  die "No PCIR signature in $romfile\n"
36      unless substr ( $romdata, $pci, 4 ) eq "PCIR";
37
38  ( my $indicator ) =
39      unpack ( 'C', substr ( $romdata, $pci + INDICATOR_OFF, 1 ) );
40  my $msg = sprintf ( "$romfile: indicator was %02x, ", $indicator );
41  $indicator &= ! ( 1 << 7 );
42  $indicator |= ( $last << 7 );
43  $msg .= sprintf ( "now %02x\n", $indicator );
44  substr ( $romdata, $pci + INDICATOR_OFF, 1 ) = pack ( 'C', $indicator );
45  warn $msg;
46
47  print $romdata;
48}
49