Atic Atac: Routine at 9A50

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	9A50	POP BC	Restore the attribute and graphic ID from the stack.
	9A51	CALL GetBlendInstruction	Call GetBlendInstruction to get the instruction to mix the graphic with the screen.
	9A54	LD ($9A78),A	Write it over the instruction at 9A78.
	9A57	CALL GetGraphicDetails	Call GetGraphicDetails to get the details of the graphic.
	9A5A	LD A,B	Fetch the width.
	9A5B	EXX	Switch to the shadow registers.
	9A5C	LD B,A	Keep the number of columns in B'.
	9A5D	LD L,$80	L'=80 (the mask for the first column).
	9A5F	EXX	Switch back to the main registers.
DrawGraphic_Transposed_Row	9A60	PUSH BC	Stash the width and height on the stack.
	9A61	PUSH DE	Stash the position in the graphic on the stack.
	9A62	PUSH HL	Stash the screen address on the stack.
DrawGraphic_Transposed_Bit	9A63	LD A,(DE)	Fetch the byte of the graphic.
	9A64	EXX	Switch to the shadow registers.
	9A65	AND L	Mask the column.
	9A66	JR Z,DrawGraphic_Transposed_Shift	Jump to DrawGraphic_Transposed_Shift if the bit is not set.
	9A68	SCF	Set the carry flag.
DrawGraphic_Transposed_Shift	9A69	RL H	Shift the bit into H'.
	9A6B	EXX	Switch back to the main registers.
	9A6C	CALL AddWidthToAddress	Call AddWidthToAddress to move down to the next row of the graphic.
	9A6F	DEC C	Decrease the height by one.
	9A70	LD A,C	Fetch the number of rows left.
	9A71	AND %00000111	Keep only bits 0-2.
	9A73	JR NZ,DrawGraphic_Transposed_Bit	Jump to DrawGraphic_Transposed_Bit until eight bits have been gathered.
	9A75	EXX	Switch to the shadow registers.
	9A76	LD A,H	Fetch the byte that was built from the column.
	9A77	EXX	Switch back to the main registers.
	9A78	NOP	This is replaced by an instruction that mixes A with the screen.
	9A79	LD (HL),A	Write A to the screen.
	9A7A	INC L	Move HL on to the next byte.
	9A7B	LD A,C	Fetch the number of rows left.
	9A7C	AND A	Jump to DrawGraphic_Transposed_Bit if there are more bytes in this row of the screen.
	9A7D	JR NZ,DrawGraphic_Transposed_Bit
	9A7F	POP HL	Restore the screen address from the stack.
	9A80	CALL ScreenPosition1PixelAbove	Call ScreenPosition1PixelAbove to move up a line.
	9A83	POP DE	Restore the position in the graphic from the stack.
	9A84	POP BC	Restore the width and height from the stack.
	9A85	EXX	Switch to the shadow registers.
	9A86	RRC L	Move the mask on to the next column.
	9A88	EXX	Switch back to the main registers.
	9A89	JR NC,DrawGraphic_Transposed_Row	Jump to DrawGraphic_Transposed_Row if there are more columns in this byte.
	9A8B	EXX	Switch to the shadow registers.
	9A8C	DEC B	Decrease the number of columns by one.
	9A8D	EXX	Switch back to the main registers.
	9A8E	RET Z	Return if all of the columns have been drawn.
	9A8F	INC DE	Move DE on to the next byte.
	9A90	JR DrawGraphic_Transposed_Row	Jump back to DrawGraphic_Transposed_Row to draw the next row of the graphic.