Atic Atac: Routine at 39504

The handler of DrawGraphic for a graphic that is flipped along the diagonal from top left to bottom right. Each row of the screen is made from a column of the graphic, from the left-hand side to the right-hand side, from the top down. This is the same as DrawGraphic_RotatedLeft except for the direction of the columns.

The handler of DrawGraphic for a graphic that is flipped along the diagonal from top left to bottom right. Each row of the screen is made from a column of the graphic, from the left-hand side to the right-hand side, from the top down. This is the same as DrawGraphic_RotatedLeft except for the direction of the columns.
DrawGraphic_Transposed	39504	POP BC	Restore the attribute and graphic ID from the stack.
	39505	CALL GetBlendInstruction	Call GetBlendInstruction to get the instruction to mix the graphic with the screen.
	39508	LD (39544),A	Write it over the instruction at 39544.
	39511	CALL GetGraphicDetails	Call GetGraphicDetails to get the details of the graphic.
	39514	LD A,B	Fetch the width.
	39515	EXX	Switch to the shadow registers.
	39516	LD B,A	Keep the number of columns in B'.
	39517	LD L,128	L'=128 (the mask for the first column).
	39519	EXX	Switch back to the main registers.
DrawGraphic_Transposed_Row	39520	PUSH BC	Stash the width and height on the stack.
	39521	PUSH DE	Stash the position in the graphic on the stack.
	39522	PUSH HL	Stash the screen address on the stack.
DrawGraphic_Transposed_Bit	39523	LD A,(DE)	Fetch the byte of the graphic.
	39524	EXX	Switch to the shadow registers.
	39525	AND L	Mask the column.
	39526	JR Z,DrawGraphic_Transposed_Shift	Jump to DrawGraphic_Transposed_Shift if the bit is not set.
	39528	SCF	Set the carry flag.
DrawGraphic_Transposed_Shift	39529	RL H	Shift the bit into H'.
	39531	EXX	Switch back to the main registers.
	39532	CALL AddWidthToAddress	Call AddWidthToAddress to move down to the next row of the graphic.
	39535	DEC C	Decrease the height by one.
	39536	LD A,C	Fetch the number of rows left.
	39537	AND %00000111	Keep only bits 0-2.
	39539	JR NZ,DrawGraphic_Transposed_Bit	Jump to DrawGraphic_Transposed_Bit until eight bits have been gathered.
	39541	EXX	Switch to the shadow registers.
	39542	LD A,H	Fetch the byte that was built from the column.
	39543	EXX	Switch back to the main registers.
	39544	NOP	This is replaced by an instruction that mixes A with the screen.
	39545	LD (HL),A	Write A to the screen.
	39546	INC L	Move HL on to the next byte.
	39547	LD A,C	Fetch the number of rows left.
	39548	AND A	Jump to DrawGraphic_Transposed_Bit if there are more bytes in this row of the screen.
	39549	JR NZ,DrawGraphic_Transposed_Bit
	39551	POP HL	Restore the screen address from the stack.
	39552	CALL ScreenPosition1PixelAbove	Call ScreenPosition1PixelAbove to move up a line.
	39555	POP DE	Restore the position in the graphic from the stack.
	39556	POP BC	Restore the width and height from the stack.
	39557	EXX	Switch to the shadow registers.
	39558	RRC L	Move the mask on to the next column.
	39560	EXX	Switch back to the main registers.
	39561	JR NC,DrawGraphic_Transposed_Row	Jump to DrawGraphic_Transposed_Row if there are more columns in this byte.
	39563	EXX	Switch to the shadow registers.
	39564	DEC B	Decrease the number of columns by one.
	39565	EXX	Switch back to the main registers.
	39566	RET Z	Return if all of the columns have been drawn.
	39567	INC DE	Move DE on to the next byte.
	39568	JR DrawGraphic_Transposed_Row	Jump back to DrawGraphic_Transposed_Row to draw the next row of the graphic.