#!/usr/bin/perl
# 
# Copyright © 2015-2020 by Vincent Slyngstad
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS LISTED ABOVE BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# 
# Except as contained in this notice, the names of the authors above
# shall not be used in advertising or otherwise to promote the sale, use
# or other dealings in this Software without prior written authorization
# from those authors.

#
# Convert a .SV file into a .BN file

# First, get the header information.

# JSW bits:
#    0-No 00000-01777
#    1-No 10000-11777
#    2-Reload
#    3-Less 8k
#   10-No pre CD
#   11-No pre USR

$half = 0;
sub getword {
  if ($half == 0) {
#   read(INPUT, $ccc, 3) || die "read: $! at ", tell(INPUT); # 3 bytes is two words.
    read(INPUT, $ccc, 3) || ($ccc = pack("CCC", 0, 0, 0)); # 3 bytes is two words.
    ($w1, $w2, $c3) = unpack("CCC", $ccc);
    $w1 += ($c3 & 0xF0) << 4;
    $w2 += ($c3 & 0x0F) << 8;
    $half = 1;
    return $w1;
  }
  $half = 0;
  return $w2;
}

@todo = @ARGV;
foreach $f (@todo) {
  open(INPUT, $f) || die "$f: $!";
  binmode(INPUT);
  @co = @pc = @fld = ();
  # The first four words
  $cs = 010000-&getword; # Core Segment Count (stored negative)
  $sf = &getword; # Starting Field (062N3)
  $sa = &getword; # Starting Address
  $jsw = &getword; # JSW
  # There are only descriptor slots for 62 core segments.
  die "$f: Can't have $cs segments!\n" unless $cs && $cs < 63;
  # Now, save each core segment doubleword.
  for ($i = 0; $i < $cs; $i++) {
    push(@co, &getword); # Core Origin
    $pc = &getword;
    push(@pc, $pc >> 6); # Page Count
    push(@fld, ($pc >> 3) & 07); # Field to load
  }
  $cs--;
  die "origin count $#co != $cs\n" unless $#co == $cs;
  die "page count $#pc != $cs\n" unless $#pc == $cs;
  die "field count $#fld != $cs\n" unless $#fld == $cs;
#warn "cs == $cs";
  # At this point, we have parsed a seemingly valid header.
  #
  # Now iterate over the various blocks and "load" them.
  seek(INPUT, 3*256/2, 0) || die "seek: $!";
  undef @core;
  for ($i = 0; $i <= $cs; $i++) {
    $base = $fld[$i]*010000 + $co[$i];
    # Load each page
#warn "Loading $pc[$i] pages\n";
    for ($j = 0; $j < $pc[$i]; $j++) {
#warn "Loading page $j from ", tell(INPUT);
#warn "got here $base";
      for ($k = 0; $k < 0200; $k++) {
        $core[$base++] = &getword;
      }
    }
    # If an odd number of pages, skip unused storage
    if ($pc[$i] & 0001) {
      for ($k = 0; $k < 0200; $k++) {
        &getword;
      }
    }
  }
  # At this point we have "loaded" the file.
  # Now to dump it back out in the correct format.
  # The checksum is simply the 12-bit sum of all bytes 
  # except field settings and leader-trailer.
# $oaddr = -2;
# for ($addr = 0; $addr <= 077777; $addr++) {
#   $oaddr = -2 if ($addr & 007) == 0;
#   if (defined $core[$addr]) {
#     printf "\n%05o)", $addr unless $addr == $oaddr;
#     printf "%04o ", $core[$addr];
#     $oaddr = $addr+1;
#   }
# }
  $of = $f; $of =~ y/A-Z/a-z/;
  $of =~ s/\.dg//; $of =~ s/\.sv//;
  $of .= ".svb";
  if (-f $of) {
#   warn "Skipping $of: exists\n";
#   next;
  }
  open(OUTPUT, ">$of") || die "$of: $!";
  binmode(OUTPUT);
  print "Writing $of\n";
  # Leader
  for ($i = 0; $i < 64; $i++) {
    print OUTPUT "\200";
  }
  $oaddr = -2;
  $cksum = 0;
  for ($addr = 0; $addr <= 077777; $addr++) {
    if (defined $core[$addr]) {
      # Change fields of $oadder is different field from $addr
      if (($oaddr & 070000) != ($addr & 070000)) {
        print OUTPUT pack("C", 0300 + (($addr >> 9) & 070));
      }
      # Output an origin if needed.
      if ($addr != $oaddr + 1) {
        $c1 = 0100 + (($addr >> 6) & 077);
        $c2 = $addr & 077;
        print OUTPUT pack("CC", $c1, $c2);
        $cksum += $c1 + $c2;
      }
      # Output the data.
      $c1 = ($core[$addr] >> 6) & 077;
      $c2 = $core[$addr] & 077;
      print OUTPUT pack("CC", $c1, $c2);
      $cksum += $c1 + $c2;
      # Remember the address.
      $oaddr = $addr;
    }
  }
  # Output the 12 bit checksum.
  $c1 = ($cksum >> 6) & 077;
  $c2 = $cksum & 077;
  print OUTPUT pack("CC", $c1, $c2);
  # Trailer
  for ($i = 0; $i < 64; $i++) {
    print OUTPUT "\200";
  }
  close(OUTPUT) || die "$of: $!";
}
exit 0;