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Routines |
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Test whether this actor is to the left of Jetman. The world wraps at 2000 so carry is set when Jetman's world X (Jetman_Position) is less than 1000 ahead of the actor.
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| Handler_Missile | AD36 | LD HL,($607A) | Fetch Jetman_Position. | |||||
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This entry point is used by the routine at AlignToRover.
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| Handler_Missile_FetchActorX | AD39 | LD C,(IX+$02) | Fetch the actor world X. | |||||
| AD3C | LD B,(IX+$03) | Fetch the high byte. | ||||||
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Return carry if HL is ahead of BC (to its right) by less than 1000 (allowing for the wrap at 2000).
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| Handler_Missile_CompareWorldX | AD3F | AND A | Clear the carry flag. | |||||
| AD40 | SBC HL,BC | Subtract the second world X. | ||||||
| AD42 | LD A,H | Fetch the high byte of the difference. | ||||||
| AD43 | AND A | Jump to Handler_Missile_NegateThenRange if the result is negative. | ||||||
| AD44 | JP M,Handler_Missile_NegateThenRange | |||||||
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Test a positive difference against the range and return carry.
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| AD47 | LD BC,$1000 | Set the range in BC to 1000. | ||||||
| AD4A | AND A | Clear the carry flag. | ||||||
| AD4B | SBC HL,BC | Subtract the range. | ||||||
| AD4D | RET | Return. | ||||||
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Call NegatePair on a negative difference, then test it against the range and invert the carry.
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| Handler_Missile_NegateThenRange | AD4E | CALL NegatePair | Call NegatePair. | |||||
| AD51 | LD BC,$1000 | Set the range in BC to 1000. | ||||||
| AD54 | AND A | Clear the carry flag. | ||||||
| AD55 | SBC HL,BC | Subtract the range. | ||||||
| AD57 | CCF | Invert the carry flag. | ||||||
| AD58 | RET | Return. | ||||||
| Prev: AD33 | Up: Map | Next: AD59 |