Alternative teleport routine
                         ----------------------------
                         J.G.Harston -- 26 April 1985

Change:                        to:
8B70 01 FE EF   LD   BC,&EFFE                              ; keys '0'-'6'
8B73 ED 78      IN   A,(C)     8B73 ED 50    IN  D,(C)
8B75 CB 4F      BIT  1,A       8B75 CB 4A    BIT 1,D       ; is '9' pressed?
8B77 C2 97 8B   JP   NZ,&8B97  8B77 20 1E    JR  NZ,&8B97  ; no
8B7A E6 10      AND  &10       8B79 3A E3 85 LD  A,(&85E3)
8B7C EE 10      XOR  &10       8B7C FE 0A    CP  &0A       ; is teleport on?
8B7E 07         RLCA           8B7E 20 17    JR  NZ,&8B97  ; no
8B7F 57         LD   D,A       8B80 3A 20 84 LD  A,(&8420) ; get ROOM
8B80 3A E3 85   LD   A,(&85E3) 8B83 3C       INC A         ; A=ROOM+1
8B83 FE 0A      CP   &0A       8B84 CB 62    BIT 4,D       ; is '6' pressed?
8B85 C2 97 8B   JP   NZ,&8B97  8B86 28 06    JR  Z,&8B8E   ; yes, update ROOM
8B88 01 FE F7   LD   BC,&F7FE  8B88 3D       DEC A
8B8B ED 78      IN   A,(C)     8B89 3D       DEC A         ; A=ROOM-1
8B8D 2F         CPL            8B8A CB 5A    BIT 3,D       ; is '7' pressed?
                               8B8C 20 E5    JR NZ,&8B73   ; no, loop back
8B8E E6 1F      AND  &1F       8B8E 00       NOP
                               8B8F 00       NOP
8B90 B2         OR   D         8B90 00       NOP
8B91 32 20 84   LD   (&8420),A
8B94 C3 12 89   JP   &8912

Operation:
When teleport is on, hold '9' down. Pressing '6' and '7' will increment and
decrement the room number.  Let go of '9' to continue playing.