#!/usr/bin/perl

die "Usage: romfill infile outfile size\n" unless $#ARGV >= 2;

$in = $ARGV[0];
$out = $ARGV[1];
$size = $ARGV[2];

die "Can't open $in: $!" unless -f $in;
system ("cp", $in, $out);
@s = stat($in);
$insize = $s[7];

open(OUT, ">> $out") or die "Can't open $out for output: $!";

for($i = 0; $i < 256; $i++) {
    push @x, $i;
}
$fill = pack "C256", @x;
$frag = $insize % 256;
$insize += syswrite(OUT, $fill, 256-$frag, $frag) if $frag;
while($insize < $size) {
    $remain = $size - $insize;
    $remain = 256 if ($remain > 256);
    $insize += syswrite(OUT, $fill, $remain);
}
close OUT;