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Routines |
Prev: 31447 | Up: Map | Next: 31637 |
Used by the routines at 31648, 62938 and 63374. Returns with one of the following values in A depending on the relative locations of the follower and his target:
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31452 | LD L,97 | Byte 97 of the follower's buffer holds his y-coordinate | ||||||||||||||||
31454 | LD A,(HL) | Pick this up in A | ||||||||||||||||
31455 | CP 155 | Is the follower on the top floor? | ||||||||||||||||
31457 | JR Z,31480 | Jump if so | ||||||||||||||||
31459 | CP 162 | Is the follower on the middle floor? | ||||||||||||||||
31461 | JR Z,31480 | Jump if so | ||||||||||||||||
31463 | CP 169 | Is the follower on the bottom floor? | ||||||||||||||||
31465 | JR Z,31480 | Jump if so | ||||||||||||||||
The follower is on a staircase. Find out whether he's going up or down and set A accordingly to make him continue.
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31467 | LD L,98 | Byte 98 of the follower's buffer holds his x-coordinate | ||||||||||||||||
31469 | LD A,(HL) | Pick this up in A | ||||||||||||||||
31470 | LD L,96 | Byte 96 holds the follower's animatory state | ||||||||||||||||
31472 | ADD A,80 | Set bit 7 of A if the follower is on a staircase at the right of the skool | ||||||||||||||||
31474 | XOR (HL) | A=1 if the follower is going upstairs, 2 if he's going downstairs | ||||||||||||||||
31475 | AND 128 | |||||||||||||||||
31477 | RLCA | |||||||||||||||||
31478 | INC A | |||||||||||||||||
31479 | RET | |||||||||||||||||
The follower is not on a staircase. Which way should he go?
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31480 | CP D | Is the follower on the same floor as the target? | ||||||||||||||||
31481 | JR NZ,31549 | Jump if not | ||||||||||||||||
The follower is on the same floor as the target. However, there may be a wall between them.
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31483 | INC L | Pick up the follower's x-coordinate in A | ||||||||||||||||
31484 | LD A,(HL) | |||||||||||||||||
31485 | SUB E | Is the follower in the same spot as his target? | ||||||||||||||||
31486 | RET Z | Return if so | ||||||||||||||||
31487 | DEC L | Pick up the follower's y-coordinate in A | ||||||||||||||||
31488 | LD A,(HL) | |||||||||||||||||
31489 | CP 169 | Is the follower on the bottom floor? | ||||||||||||||||
31491 | JR NZ,31501 | Jump if not | ||||||||||||||||
The follower and target are both on the bottom floor, so the follower should simply move either left or right.
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31493 | INC HL | L=98 | ||||||||||||||||
31494 | LD A,(HL) | A=follower's x-coordinate | ||||||||||||||||
31495 | CP E | Set the carry flag if the follower should go right | ||||||||||||||||
31496 | LD A,3 | A=3 if the follower should go left, 4 if he should go right | ||||||||||||||||
31498 | ADC A,0 | |||||||||||||||||
31500 | RET | |||||||||||||||||
The follower and target are both on the middle floor or both on the top floor.
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31501 | CP 162 | 162=middle floor | ||||||||||||||||
31503 | INC HL | L=98 | ||||||||||||||||
31504 | LD A,57 | 57=x-coordinate of the wall between the Reading and Map Rooms | ||||||||||||||||
31506 | JR NZ,31510 | Jump if the follower and target are on the top floor | ||||||||||||||||
31508 | LD A,38 | 38=x-coordinate of the wall between the White and Exam Rooms | ||||||||||||||||
31510 | CP (HL) | Compare the follower's x-coordinate with that of the wall | ||||||||||||||||
31511 | JR C,31531 | Jump if the follower is to the right of the wall | ||||||||||||||||
31513 | CP E | Is the target character to the left of the wall? | ||||||||||||||||
31514 | JR NC,31494 | Jump if so | ||||||||||||||||
The follower is on the left side of the skool and must go downstairs to get to the target on the other side of the skool.
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31516 | LD A,(HL) | A=follower's x-coordinate | ||||||||||||||||
31517 | CP 12 | 12=x-coordinate of the tops of the staircases at the left of the skool | ||||||||||||||||
31519 | JR NZ,31496 | Jump unless the follower is at the top of a staircase | ||||||||||||||||
31521 | LD L,96 | Byte 96 of the follower's buffer holds his animatory state | ||||||||||||||||
31523 | LD A,4 | A=4 will make the follower turn round if facing left | ||||||||||||||||
31525 | BIT 7,(HL) | Is the follower facing left? | ||||||||||||||||
31527 | RET Z | Return if so | ||||||||||||||||
31528 | LD A,2 | A=2 will make the follower go down the stairs | ||||||||||||||||
31530 | RET | |||||||||||||||||
The follower is on the right side of the skool. Is the target there too?
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31531 | CP E | Is the target character to the right of the wall? | ||||||||||||||||
31532 | JR C,31494 | Jump if so | ||||||||||||||||
31534 | LD A,(HL) | A=follower's x-coordinate | ||||||||||||||||
31535 | CP 77 | 77=x-coordinate of the tops of the staircases at the right of the skool | ||||||||||||||||
31537 | JR NZ,31496 | Jump unless the follower is at the top of a staircase | ||||||||||||||||
31539 | LD L,96 | Byte 96 of the follower's buffer holds his animatory state | ||||||||||||||||
31541 | LD A,3 | A=3 will make the follower turn round if facing right | ||||||||||||||||
31543 | BIT 7,(HL) | Is the follower facing right? | ||||||||||||||||
31545 | RET NZ | Return if so | ||||||||||||||||
31546 | LD A,2 | A=2 will make the follower go down the stairs | ||||||||||||||||
31548 | RET | |||||||||||||||||
The follower and target are on different floors.
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31549 | JR NC,31565 | Jump if the target is on a floor above the follower | ||||||||||||||||
31551 | CP 162 | 162=middle floor | ||||||||||||||||
31553 | INC HL | L=98 | ||||||||||||||||
31554 | LD A,57 | 57=x-coordinate of the wall between the Reading and Map Rooms | ||||||||||||||||
31556 | JR NZ,31560 | Jump if the follower is on the top floor | ||||||||||||||||
31558 | LD A,38 | 38=x-coordinate of the wall between the White and Exam Rooms | ||||||||||||||||
31560 | CP (HL) | Compare the follower's x-coordinate with that of the wall | ||||||||||||||||
31561 | JR NC,31516 | Jump if the follower is to the left of the wall (and so needs to go to the top of a staircase on the left) | ||||||||||||||||
31563 | JR C,31534 | Jump if the follower is to the right of the wall (and so needs to go to the top of a staircase on the right) | ||||||||||||||||
The target is on a floor above the follower. Which staircase should the follower use?
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31565 | LD A,D | A=target's y-coordinate | ||||||||||||||||
31566 | LD D,155 | 155=top floor | ||||||||||||||||
31568 | CP 162 | 162=middle floor | ||||||||||||||||
31570 | LD A,57 | 57=x-coordinate of the wall between the Reading and Map Rooms | ||||||||||||||||
31572 | JR C,31578 | Jump if the target is above the middle floor | ||||||||||||||||
31574 | LD D,162 | 162=middle floor | ||||||||||||||||
31576 | LD A,38 | 38=x-coordinate of the wall between the White and Exam Rooms | ||||||||||||||||
31578 | CP E | Compare the target's x-coordinate with that of the wall | ||||||||||||||||
31579 | LD E,97 | Signal: target is to the right of the wall | ||||||||||||||||
31581 | JR C,31585 | Jump if the target is to the right of the wall | ||||||||||||||||
31583 | LD E,1 | Signal: target is to the left of the wall | ||||||||||||||||
31585 | LD A,(HL) | A=follower's y-coordinate | ||||||||||||||||
31586 | CP 169 | 169=bottom floor | ||||||||||||||||
31588 | INC HL | L=98 | ||||||||||||||||
31589 | JR NZ,31622 | Jump if the follower is on the middle floor | ||||||||||||||||
31591 | LD A,19 | 19=x-coordinate of the bottoms of the staircases at the left of the skool | ||||||||||||||||
31593 | DEC E | Is the target to the left of the wall? | ||||||||||||||||
31594 | JR Z,31598 | Jump if so | ||||||||||||||||
31596 | LD A,70 | 70=x-coordinate of the bottoms of the staircases at the right of the skool | ||||||||||||||||
31598 | CP (HL) | Compare this with the follower's x-coordinate | ||||||||||||||||
31599 | CCF | Set the carry flag if the follower should go right | ||||||||||||||||
31600 | JR NZ,31496 | Jump if the follower is not at the bottom of a staircase | ||||||||||||||||
31602 | LD L,96 | Byte 96 of the follower's buffer holds his animatory state | ||||||||||||||||
31604 | CP 19 | 19=x-coordinate of the bottoms of the staircases at the left of the skool | ||||||||||||||||
31606 | LD A,1 | A=1 will make the follower go upstairs | ||||||||||||||||
31608 | JR Z,31616 | Jump if the follower should go up a staircase at the left of the skool | ||||||||||||||||
31610 | BIT 7,(HL) | Is the follower facing right? | ||||||||||||||||
31612 | RET NZ | Jump if so | ||||||||||||||||
31613 | LD A,4 | A=3 will make the follower turn round and face right | ||||||||||||||||
31615 | RET | |||||||||||||||||
31616 | BIT 7,(HL) | Is the follower facing left? | ||||||||||||||||
31618 | RET Z | Return (with A=1) if so | ||||||||||||||||
31619 | LD A,3 | A=3 will make the follower turn round and face left | ||||||||||||||||
31621 | RET | |||||||||||||||||
The follower is on the middle floor, and the target is on the top floor.
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31622 | LD A,38 | 38=x-coordinate of the wall between the White and Exam Rooms | ||||||||||||||||
31624 | CP (HL) | Compare this with the follower's x-coordinate | ||||||||||||||||
31625 | LD A,97 | Signal: follower is to the right of the wall | ||||||||||||||||
31627 | JR C,31631 | Jump if the follower is to the right of the wall | ||||||||||||||||
31629 | LD A,1 | Signal: follower is to the left of the wall | ||||||||||||||||
31631 | CP E | Is the target on the same side of the skool? | ||||||||||||||||
31632 | JR Z,31591 | Jump if so (follower must go up the nearest staircase) | ||||||||||||||||
31634 | CCF | Set the carry flag if the follower must go down a staircase at the right of the skool, and reset it if he must go down a staircase at the left of the skool | ||||||||||||||||
31635 | JR 31561 |
Prev: 31447 | Up: Map | Next: 31637 |