Splitting Images: Routine at E63F

E63F: Remove Player Cursor Attributes

Used by the routines at Controls_CheckRight, Controls_CheckLeft, Remove_PlayerCursor and F85D.
Less "remove" and more "replace"; this routine erases the players cursor attributes, but it doesn't leave a hole - it replaces the attributes with the values they were prior to it being originally drawn. This is the 4x4 block of attributes which were behind the cursor before it was initially painted.
Remove_PlayerCursorAttributes	E63F	LD HL,$E5D0	Load HL with SavedAttributesBlock.
This is a pointer to the starting attribute buffer location of the players cursor.
	E642	LD DE,($E5E2)	Load DE with *Cursor_AttributePointer.
The cursor block is 04x04 (04 rows of 04 bytes).
	E646	LD B,$04	Set a counter in B for 04 rows.
Remove_PlayerCursorAttributes_Loop	E648	PUSH BC	Stash the row counter on the stack.
	E649	LD BC,$0004	Copy 0004 bytes from the stored attributes to the attribute buffer.
	E64C	LDIR
One full row is 20 bytes, so this is 04 bytes less than one row. Hence this moves down one row, but back to the start of the line.
	E64E	EX DE,HL	Add 001C to the attribute buffer position.
	E64F	LD BC,$001C
	E652	ADD HL,BC
	E653	EX DE,HL
	E654	POP BC	Restore the row counter from the stack.
	E655	DJNZ Remove_PlayerCursorAttributes_Loop	Decrease the row counter by one and loop back to Remove_PlayerCursorAttributes_Loop until all the rows have been updated.
	E657	RET	Return.