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Routines |
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Used by the routine at ApplyCollisionEffects.
Halves the speed of the player's ship in each direction, unless the speed of the object that was hit is in the opposite direction.
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| SlowShip | 8F1E | LD A,($8CB1) | Fetch the value from 8CB1. | |||||||
| 8F21 | AND A | Test it. | ||||||||
| 8F22 | RET NZ | Return if it is not zero. | ||||||||
| 8F23 | LD D,(IY+$19) | Fetch the horizontal speed of the player into DE. | ||||||||
| 8F26 | LD E,(IY+$1A) | |||||||||
| 8F29 | LD A,D | Compare its sign with that of the object. | ||||||||
| 8F2A | XOR (IX+$07) | |||||||||
| 8F2D | BIT 7,A | Jump to SlowShip_Vertical if they are different. | ||||||||
| 8F2F | JR NZ,SlowShip_Vertical | |||||||||
| 8F31 | SRA D | Halve the horizontal speed... | ||||||||
| 8F33 | RR E | |||||||||
| 8F35 | LD (IY+$19),D | ...and store it. | ||||||||
| 8F38 | LD (IY+$1A),E | |||||||||
| SlowShip_Vertical | 8F3B | LD D,(IY+$1B) | Fetch the vertical speed of the player into DE. | |||||||
| 8F3E | LD E,(IY+$1C) | |||||||||
| 8F41 | LD A,D | Compare its sign with that of the object. | ||||||||
| 8F42 | XOR (IX+$09) | |||||||||
| 8F45 | BIT 7,A | Test bit 7. | ||||||||
| 8F47 | RET NZ | Return if they are different. | ||||||||
| 8F48 | SRA D | Halve the vertical speed... | ||||||||
| 8F4A | RR E | |||||||||
| 8F4C | LD (IY+$1B),D | ...and store it. | ||||||||
| 8F4F | LD (IY+$1C),E | |||||||||
| 8F52 | RET | Return. | ||||||||
| 8F53 | DEFB $00 | |||||||||
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