Everyone's a Wally: Routine at E77A

E77A: Clear Character Items

Used by the routine at E41D.
ClearCharacterItems	E77A	PUSH HL	Stash HL, BC and DE on the stack.
	E77B	PUSH BC
	E77C	PUSH DE
	E77D	LD IX,$81F8	IX=ScreenBuffer_Locations.
The number of rows to blank.
	E781	LD C,$20	C=20 (rows).
Fetch the screen buffer address.
ClearCharacterItems_NextLine	E783	LD L,(IX+$00)	L=IX+00.
	E786	LD H,(IX+$01)	H=IX+01.
The number of columns to blank.
	E789	LD B,$0F	B=0F.
ClearCharacterItems_Loop	E78B	LD (HL),$00	Write 00 to *HL.
	E78D	INC HL	Increment HL by one.
	E78E	DJNZ ClearCharacterItems_Loop	Decrease counter by one and loop back to ClearCharacterItems_Loop until counter is zero.
Move onto the next line down in the screen buffer.
	E790	INC IX	Increment IX by two.
	E792	INC IX	Increment IX by two.
Keep looping until all rows have been blanked.
	E794	DEC C	Decrease C by one.
	E795	JR NZ,ClearCharacterItems_NextLine	Jump to ClearCharacterItems_NextLine until C is zero.
Restore the registers and return.
	E797	POP DE	Restore DE, BC and HL from the stack.
	E798	POP BC
	E799	POP HL
	E79A	RET	Return.