Routines
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C7C4: Nudge Object North South
Sets the adjustment of the speed in X of an object, to bring it a step closer to the middle line of an arch that goes north and south.
Input
IX Address of the arch object
IY Address of the object
Step the object towards the north-south middle line.
NudgeObjectNorthSouth C7C4 LD A,(IX+$09) Fetch the X coordinate of the middle of the doorway.
C7C7 CP (IY+$01) Compare it with the X coordinate of the object.
C7CA JR Z,NudgeObjectsToArch_Restore Jump to NudgeObjectsToArch_Restore if the object is in the middle.
C7CC LD A,$01 Set the adjustment to 01.
C7CE JR NC,NudgeObjectNorthSouth_Set Jump to NudgeObjectNorthSouth_Set if the object is west of the middle.
C7D0 NEG Make the adjustment negative.
NudgeObjectNorthSouth_Set C7D2 LD (IY+$0E),A Set the adjustment of the speed in X of the object.
This entry point is used by the routine at NudgeObjectEastWest.
NudgeObjectsToArch_Restore C7D5 POP BC Restore the number of objects left from the stack.
This entry point is used by the routine at NudgeObjectsToArch.
NudgeObjectsToArch_Advance C7D6 ADD IY,DE Point IY at the next object.
C7D8 DJNZ NudgeObjectsToArch_Next Jump to NudgeObjectsToArch_Next until all of the objects have been done.
C7DA RET Return.
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