| Routines

F308: Deal with Sam when he has knocked on or is opening a door

Used by the routine at 74D8 when bit 6 at 7FFC is set (by the routine at F2F0), indicating that Sam has knocked on or is opening a door.
Input
H | 0xE6 (Sam)
F308 | XOR A | Clear Sam's status flags at 7FFC
F309 | LD ($7FFC),A
F30C | PUSH HL | Save Sam's character number (in H) briefly
F30D | CALL $EB13 | Obtain descriptors for Sam's current location
F310 | POP HL | Restore Sam's character number to H
F311 | CP $04 | Is Sam standing behind or in front of a closed door?
F313 | JR NZ,$F324 | Jump if not
F315 | LD L,$04 | Point HL at byte 0x04 of Sam's buffer
F317 | BIT 0,(HL) | Is Sam indoors?
F319 | JR NZ,$F327 | Jump if so
F31B | CALL $F2A8 | Open the door if Sam has the key, or signal that he has knocked on the door
F31E | JR $F324 |
F320 | EX DE,HL | These three instructions are never executed; but if the relative jump above were made only when the carry flag is reset (meaning Sam has opened the door), these instructions would set bit 5 of the door knock status flags for the door (see 7FAA)
F321 | SET 5,(HL)
F323 | EX DE,HL
F324 | JP $EC7B | Lower Sam's arm and make a sound effect
Sam is standing behind a closed door.
F327 | CALL $EC7B | Lower Sam's arm and make a sound effect
F32A | LD H,$E6 | 0xE6=Sam
This entry point is used by the routines at F600 and F7BF.
F32C | LD D,H | D=character number
F32D | CALL $F293 | Check whether the door is open
F330 | EX DE,HL | Restore the character number to H
F331 | RET NZ | Return if the door is open
F332 | EX DE,HL | Point HL at the door status flags
F333 | JP $F2B3 | Open the door