Routines
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76BC: Deal with a character who is at the entrance to a building
Used by the routine at EBBB. On entry, the bit set in A indicates the direction in which the character is going to move next:
Bit Direction
7 Left
6 Right
5 Up and to the left
4 Up and to the right
3 Down and to the left
2 Down and to the right
Also on entry, the zero flag is set if the character is indoors. If the character is Sam, we also check whether he's entering a house other than no. 19 without a key.
Input
A Direction indicator (0x80, 0x40, 0x20, 0x10, 0x08 or 0x04)
B Third byte of the character's location descriptor (see EB13)
H Character number (0xD7-0xE6)
L 4
76BC JR NZ,$76C2 Jump unless the character is indoors
76BE AND B Is the character going to leave the building?
76BF RET NZ Return if not
76C0 INC (HL) Set the character's z-coordinate to 2
76C1 RET
76C2 AND B Is the character going to enter the building?
76C3 JR Z,$76C0 Jump if not
76C5 LD A,H A=character number
76C6 CP $E6 Is this Sam?
76C8 RET NZ Return if not
76C9 BIT 0,B Does the entrance have a door?
76CB RET Z Return if not
76CC CALL $F293 Point HL at the status flags for the door that Sam is standing next to (see 7FF0)
76CF LD A,L A=LSB of the address of the door status flags (0xF0-0xF9)
76D0 CP $F5 Is Sam standing in the doorway of no. 19?
76D2 JR Z,$76D7 Jump if so
76D4 LD A,(HL) Pick up the door status flags for the doorway Sam is standing in
76D5 AND $F8 Set the zero flag if the door requires no key to unlock it
76D7 LD H,$E6 0xE6=Sam
76D9 RET Z Return if the door requires no key to unlock it
76DA JP $7A39 Check whether Sam has entered a house through the front door without a key
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