Routines
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6C82: Get Map Distance
Used by the routine at UpdateCurrentObject.
Finds the distance between the first co-ordinate of the player's map position at PlayerMapPosition and the value in DE. The carry flag is set when the distance is less than 60.
Input
DE Map position
Output
HL Distance
F The carry flag is set when the distance is less than 60
GetMapDistance 6C82 LD HL,($5E05) Fetch the player's X position on the map (PlayerMapPosition).
6C85 AND A HL=HL - DE.
6C86 SBC HL,DE
6C88 JR NC,GetMapDistance_Compare Jump to GetMapDistance_Compare if there was no carry.
6C8A CALL NegateHL Call NegateHL.
GetMapDistance_Compare 6C8D PUSH HL Stash HL on the stack.
6C8E LD DE,$0060 Set the furthest distance in view, 0060.
6C91 AND A Compare the distance with the furthest distance in view.
6C92 SBC HL,DE
6C94 POP HL Restore HL from the stack.
6C95 RET Return.
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