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Routines |
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Used by the routine at 34574.
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| 36593 | LD IY,32989 | Point IY at the first byte of the first vertical guardian definition at 32989 | ||
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The guardian-moving loop begins here.
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| 36597 | LD A,(IY+0) | Pick up the first byte of the guardian definition | ||
| 36600 | CP 255 | Have we dealt with all the guardians yet? | ||
| 36602 | RET Z | Return if so | ||
| 36603 | INC (IY+1) | Increment the guardian's animation frame | ||
| 36606 | RES 2,(IY+1) | Reset the animation frame to 0 if it overflowed to 4 | ||
| 36610 | LD A,(IY+2) | Pick up the guardian's pixel y-coordinate | ||
| 36613 | ADD A,(IY+4) | Add the current y-coordinate increment | ||
| 36616 | CP (IY+5) | Has the guardian reached the highest point of its path (minimum y-coordinate)? | ||
| 36619 | JR C,36631 | If so, jump to change its direction of movement | ||
| 36621 | CP (IY+6) | Has the guardian reached the lowest point of its path (maximum y-coordinate)? | ||
| 36624 | JR NC,36631 | If so, jump to change its direction of movement | ||
| 36626 | LD (IY+2),A | Update the guardian's pixel y-coordinate | ||
| 36629 | JR 36639 | |||
| 36631 | LD A,(IY+4) | Negate the y-coordinate increment; this changes the guardian's direction of movement | ||
| 36634 | NEG | |||
| 36636 | LD (IY+4),A | |||
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Now that the guardian's movement has been dealt with, time to draw it.
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| 36639 | LD A,(IY+2) | Pick up the guardian's pixel y-coordinate | ||
| 36642 | AND 127 | Point DE at the entry in the screen buffer address lookup table at 33536 that corresponds to the guardian's pixel y-coordinate | ||
| 36644 | RLCA | |||
| 36645 | LD E,A | |||
| 36646 | LD D,131 | |||
| 36648 | LD A,(DE) | Point HL at the address of the guardian's location in the screen buffer at 24576 | ||
| 36649 | OR (IY+3) | |||
| 36652 | LD L,A | |||
| 36653 | INC DE | |||
| 36654 | LD A,(DE) | |||
| 36655 | LD H,A | |||
| 36656 | LD A,(IY+1) | Pick up the guardian's animation frame (0-3) | ||
| 36659 | RRCA | Multiply it by 32 | ||
| 36660 | RRCA | |||
| 36661 | RRCA | |||
| 36662 | LD E,A | Point DE at the graphic data for the appropriate guardian sprite (at 33024+A) | ||
| 36663 | LD D,129 | |||
| 36665 | LD C,1 | Draw the guardian to the screen buffer at 24576 | ||
| 36667 | CALL 36852 | |||
| 36670 | JP NZ,36102 | Kill Willy if the guardian collided with him | ||
| 36673 | LD A,(IY+2) | Pick up the guardian's pixel y-coordinate | ||
| 36676 | AND 64 | Point HL at the address of the guardian's location in the attribute buffer at 23552 | ||
| 36678 | RLCA | |||
| 36679 | RLCA | |||
| 36680 | ADD A,92 | |||
| 36682 | LD H,A | |||
| 36683 | LD A,(IY+2) | |||
| 36686 | RLCA | |||
| 36687 | RLCA | |||
| 36688 | AND 224 | |||
| 36690 | OR (IY+3) | |||
| 36693 | LD L,A | |||
| 36694 | LD A,(IY+0) | Pick up the guardian's attribute byte | ||
| 36697 | CALL 36447 | Set the attribute bytes for the guardian | ||
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The current guardian definition has been dealt with. Time for the next one.
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| 36700 | LD DE,7 | Point IY at the first byte of the next vertical guardian definition | ||
| 36703 | ADD IY,DE | |||
| 36705 | JR 36597 | Jump back to deal with the next vertical guardian | ||
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