Sherlock: Routine at 62740

62740: Attribute Up

Used by the routine at Drawing. Moves the attribute address one row up. The attribute file begins at 22528 so a high byte of 87 means the step left the screen.
AttributeUp	62740	PUSH AF	Keep the colour and the pen, and step the screen pointer back one attribute row.
	62741	PUSH DE
	62742	LD DE,32
	62745	AND A
	62746	SBC HL,DE
	62748	LD A,H	Jump ahead to AttributeUp_Next if the high byte of the address is not 87.
	62749	CP 87
	62751	JR NZ,AttributeUp_Next
	62753	ADD HL,DE	Undo the step that passed the top row.
AttributeUp_Next	62754	POP DE	Restore the colour from the stack.
	62755	POP AF	Restore the colour from the stack.
	62756	RET	Return.
View the equivalent code in; The Hobbit