#! /usr/bin/perl

use autodie;

sub intify ($) {
  my ($n) = @_;
  if ($n =~ /^0/) { $n = oct $n; }
  return $n;
}

my $MEM = "";
my $BASE = 0x4009;
my $LIMIT = 0x8000;

for my $a (@ARGV) {
  $a =~ /^(\w+):(.*)$/ or die "bad spec ADDR:FILE";
  my $addr = intify $1;
  my $file = $2;

  my $body = "";
  open my $fh, "<", $file;
  READ: for (;;) {
    sysread $fh, my $buf, 4096;
    last READ unless length $buf;
    $body .= $buf;
  }
  close $fh;

  $addr >= $BASE && $LIMIT >= $addr + length $body
    or die "out of bounds";

  $addr -= $BASE;
  my $end = $addr + length $body;
  my $before = $addr > length $MEM
    ? $MEM . "\0" x ($addr - length $MEM)
    : substr $MEM, 0, $addr;
  my $after = $end <= length $MEM
    ? ""
    : substr $MEM, $end;
  $MEM = $before . $body . $after;
}

syswrite STDOUT, $MEM;