-if size_byte == 0:
- # If the caller left the size field blank then we will fill it in,
- # also rounding the whole input to a multiple of 512 bytes.
- data = fin.read()
- # +1 because we need a byte to store the checksum.
- size = len(data) + 1
- # Round up to next multiple of 512.
- size += 511
- size -= size % 512
- if size >= 65536:
- sys.exit("%s: option ROM size too large" % sys.argv[1])
+size = size_byte * 512
+if len(data) > size:
+ sys.stderr.write('error: ROM is too large (%d > %d)\n' % (len(data), size))
+ sys.exit(1)
+elif len(data) < size:
+ # Add padding if necessary, rounding the whole input to a multiple of
+ # 512 bytes according to the third byte of the input.