Jet Set Willy Room Specification
                     ================================

Room layout
-----------
000-127 &00-&7F: Room blocks
Each byte specified four room blocks, starting at the top-lefthand corner of
the screen. Each byte encodes the blocks as %aabbccdd encoding the blocks
aa,bb,cc,dd from left to right. Each block can be 00, 01, 10 or 11 representing
Background, Floor, Wall and Nasty.

Room name
---------
128-159 &80-&9F: Room name in ASCII
The original JSW engine indexes into the character table in ROM. Consequently
characters<&20 will display the contents of &3C00-&3CFF, solid blocks in the
default Spectrum ROM. Characters>&7F will read character matrices from the
screen at &4000-&47FF. Some JSW engines allow extra characters.

Character definitions
---------------------
160-168 &A0-&A8: Background attribute, bitmap - block 00
169-177 &A9-&B1: Floor      attribute, bitmap - block 01
178-186 &B2-&BA: Wall       attribute, bitmap - block 10
187-195 &BB-&C3: Nasty      attribute, bitmap - block 11
196-204 &C4-&CC: Slope      attribute, bitmap
205-213 &CD-&D5: Conveyor   attribute, bitmap

Slope & conveyor definitions
----------------------------
214     &D6    : Conveyor direction: 0=left, 1=right, 2=off, 3=sticky
215-216 &D7-&D8: Slope start position    = &5E00+row*32+col
217     &D9    : Slope length

218     &DA    : Slope direction: 0=left, 1=right
219-220 &DB-&DC: Conveyor start position = &5E00+row*32+col
221     &DD    : Conveyor length

Other info
----------
222     &DE    : b0-b2: Border
                 b3-b7: spare
                 Geoff Mode: b6-b7: Number and type of sprites to use for Willy
                                    00=lower four sprites
                                    01=upper four sprites
                                    10=all eight sprites, facing forward
                                    11=all eight sprites, facing backwards
                 jsw128:     b7=1 : SuperJump ON for this room
223     &DF    : spare
                 Geoff Mode: b7   : lives sprite subpage
                 jsw128:            guardian class table
224     &E0    : spare
                 Geoff Mode:        lives sprite page

Object
------
225-232 &E1-&E8: Object bitmap

Room exits
----------
233     &E9    : Room left
                 jgh:        Room top-left
234     &EA    : Room right
                 jgh:        Room top-right
235     &EB    : Room up
236     &EC    : Room down
237     &ED    : spare
                 Geoff Mode: Willy sprite page
                 jsw128:     if b7=1, Willy Sprite page
                 jgh:        Room bottom-left
238-239 &EE-&EF: spare
                 Geoff Mode: patch vector, called every tick if <>&0000
                 jgh:        &EE:Room bottom-right

Guardians
---------
240-255 &F0-&FF: Guardian table, two bytes per guardian, terminated
                 with &FF in the first byte.


Version History
---------------
1.00 18-Mar-1985 Original version.
1.10 25-Nov-2002 Added Geoff Mode and jsw128.