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54990: Test Edge Overlap
Used by the routine at TestGroupObjects.
Compares a patched position with a patched edge that has been moved back by four. The carry is set when the position is below that edge. TestGroupObjects patches both operands before the call.
Both operands are patched before the call. The edge is moved back by four and the position is compared with it.
TestEdgeOverlap 54990 LD DE,0 Move the patched edge back by four.
54993 DEC DE
54994 DEC E
54995 DEC E
54996 DEC E
54997 LD HL,0 Subtract that edge from the patched position.
55000 AND A
55001 SBC HL,DE
55003 RET C Return when the position is below the edge.
Continue on to TestBlockOverlap.
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