seti $printhelp = $printhelp
seti $help = $help
if $help = 1
  echo 'Western Digital ROYL check ram.'
  echo 'This requires the text variable "file" to be set.'
  echo '"file" is the name of the ram file.'

  if $printhelp = 1
    exit 0
  endif
  echo 'Hit ENTER to continue...'
  userinput $choicestring
  previousscript
endif

include good_subroutines.osc

# set a blank string variable to compare with user input
# make sure not to set this anyplace else
sets $null = ""

# set this to itself for use with the menu system
# make sure not to set this anyplace else
# if it was not previously set it will = 0
seti $using_menu = $using_menu

# set the file name to be read
while 1 = 1
  variablecheck $file
  if $error_level < 16
    seti $ask = 1
  elseif $using_menu = 1
    seti $ask = 1
  endif
  if $ask = 1
    echo "Enter file name:"
    userinput $choicestring
    if $choicestring != $null
      sets $file = $choicestring
      break
    else
      echo "Choice cannot be blank!"
    endif
  else
    break
  endif
done

getfilesize $file
seti $file_size = $error_level
if $file_size < 0
  echo "ERROR! File " $file " not found!"
  previousscript
endif
echo "Reading the ram file"
seti $ram_size = $file_size
scratchpadsize $ram_size
clearscratchpad
readscratchpad $file 0 0 $ram_size

gosub process_ram


previousscript
end




subroutine process_ram
  echo "processing ram"

  # search for modules and check them
  echo "Searching for modules."
  sets $header_check = "ROYL"
  seti $position = 0
  seti $search_end = $ram_size - 4
  while $position < $search_end
    sets $header = scratchpad $position 4
    if $header = $header_check
      # process the module
      seti $working_offset = $position
      #echo "Header:"
      #printscratchpad $working_offset 4
      seti $working_offset = $position + 8
      seti $mod_id = scratchpad $working_offset w
      hex
      #echo "Module ID = 0x" $mod_id

      # find how many sectors the module contains
      seti $working_offset = $position + 0xa
      seti $mod_length_sectors = scratchpad $working_offset
      seti $working_offset = $position + 0xb
      seti $tempnum = scratchpad $working_offset
      seti $tempnum = $tempnum > 8
      seti $mod_length_sectors = $mod_length_sectors + $tempnum

      #echo "Size in sectors = 0x" $mod_length_sectors
      seti $working_offset = $position + 0xc
      seti $checksum = scratchpad $working_offset dw
      #echo "32 bit checksum = 0x" $checksum
      seti $working_offset = $position + 0x10
      #echo "Mod version:"
      #printscratchpad $working_offset 8
      decimal

      seti $module_size = $mod_length_sectors * 512
      seti $calculated_checksum = 0
      seti $count = 0
      while $count < $module_size
        seti $working_offset = $position + $count
        if $working_offset > $search_end
          echo "end of module is past end of rom"
          break
        endif
        seti $dword = scratchpad $working_offset dw
        seti $calculated_checksum = $calculated_checksum + $dword
        seti $count = $count + 4
        # skip the actual checksum bytes
        if $count = 0xc
          seti $count = $count + 4
        endif
      done
      seti $calculated_checksum = $calculated_checksum & 0xffffffff
      seti $calculated_checksum = 0xffffffff - $calculated_checksum
      seti $calculated_checksum = $calculated_checksum + 1

      hex
      if $checksum = $calculated_checksum
        sets $checkstring = " calulated=0x" $calculated_checksum " (good)"
      else
        sets $checkstring = " calulated=0x" $calculated_checksum " (bad)"
      endif
      echo "pos=0x" $position " ModID=0x" $mod_id " size=0x" $module_size $checkstring
      decimal
    endif
    seti $position = $position + 512
  done
endsubroutine