Castle Frankenstein
This is a rough description of the Castle Frankenstein data and code file. The version reverse engineered was the BBC B version and may differ on others.
Files[edit]
The following files are use for Castle Frankenstein:
- $.FRANK2 - code and data
$.FRANK2[edit]
All locations are files specific, as the file is relocated to 0xC00, to convert to memory address, add 0xC00 to all pointers.
Pointers[edit]
As the file combines both code and data there is some overlap between permanent code and reused data areas. If the data area is reused it has been marked with a (temp). All pointers are 16 bit big endian pointers to memory.
| Location | Size | Usage | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0x0000 | 2 | Pointer to messages | |||||||||||||||||||||
| 0x0002 | 2 | Pointer to 0x4608 | |||||||||||||||||||||
| 0x0004 | 2 | Pointer to 0x4be4 | |||||||||||||||||||||
| 0x0006 | 2 | Pointer to verbs | |||||||||||||||||||||
| 0x000a | 2 | Null | |||||||||||||||||||||
| 0x000c | 2 | Null | |||||||||||||||||||||
| 0x000e | 2 | Pointer to location text | |||||||||||||||||||||
| 0x0010 | 2 | Null | |||||||||||||||||||||
| 0x0012 | 2 | Pointer to dictionary | |||||||||||||||||||||
| 0x0012 | 1 | (temp) Length of 0x4608 block | |||||||||||||||||||||
| 0x0015 | 1 | (temp) High nibble of 0x4608 block | |||||||||||||||||||||
| 0x0016 | 1 | (temp) Low nibble of 0x4608 block | |||||||||||||||||||||
| 0x0017 | 1 | Counter for 0x4608 block | |||||||||||||||||||||
| 0x0045 | 1 | OSFILE Block:
| |||||||||||||||||||||
| 0x00d3 | 255 | Object Starting Location | |||||||||||||||||||||
| 0x0200 | 1 | (temp) Status Block
| |||||||||||||||||||||
| 0x0264 | 255 | (temp) Inventory (in-game) | |||||||||||||||||||||
| 0x0364 | 1 | Object Descriptions | |||||||||||||||||||||
| 0x0700 | 1 | Room Exits | |||||||||||||||||||||
| 0x0e00 | 1 | System Messages | |||||||||||||||||||||
| 0x1ef8 | 1 | Location Text | |||||||||||||||||||||
| 0x3c44 | 1 | Messages | |||||||||||||||||||||
| 0x4608 | 1 | Unknown | |||||||||||||||||||||
| 0x4be4 | 1 | Unknown | |||||||||||||||||||||
| 0x4dd8 | 1 | Verbs | |||||||||||||||||||||
| 0x4dd8 | 1 | Nouns | |||||||||||||||||||||
| 0x4dd8 | 1 | Dictionary |
Room Exits[edit]
Room exits are defined as one byte, pointing to the destination room for each of the possible directions in the order:
- North
- South
- East
- West
- Up
- Down
Message Strings[edit]
Messages strings are read a byte at a time. Each byte is an index in the dictionary.
The strings are terminated by a 0x00
Verbs, nouns and dictionary are encoded with a roll right to prevent viewing.
Verbs and Nouns are a list of words with the format: WORD (encoded, terminated with a bit 7 set) WORD number (not encoded) Synonyms have the same word number.
The dictionary is a list of words terminated with bit 7 set. Indexing starts at 1, then it goes sequentially.
C16 = 33 & 0xf = 3 c15 = 33 & 0xf0 >> 4 = 3 c14 = c16 + c15 = 6
