Alien 8: Routine at 53433

Used by the routine at PrintSprite.

Draws the lines of a sprite one after the other. For each line the code jumps into the unrolled code, at a place that depends on the width of the sprite, and that is set by the jump that is changed by PrintSprite. The code for a sprite that is not on a byte boundary takes a pair of bytes off the stack, which are the mask and the data, shifts them across the two bytes of the buffer that they fall into with the table of shifted bytes in H, and keeps what is left of the second byte to go with the next pair. A sprite on a byte boundary jumps into DrawAlignedColumns instead.

Used by the routine at PrintSprite. Draws the lines of a sprite one after the other. For each line the code jumps into the unrolled code, at a place that depends on the width of the sprite, and that is set by the jump that is changed by PrintSprite. The code for a sprite that is not on a byte boundary takes a pair of bytes off the stack, which are the mask and the data, shifts them across the two bytes of the buffer that they fall into with the table of shifted bytes in H, and keeps what is left of the second byte to go with the next pair. A sprite on a byte boundary jumps into DrawAlignedColumns instead.
Jump into the unrolled columns.
DrawLines	53433	EX AF,AF'	Copy A to A'.
	53434	LD A,(BC)	Fetch the first byte of the buffer.
DrawLines_Jump	53435	JR DrawLines_Jump	Jump into the unrolled columns.
The patched jump at DrawLines_Jump lands here when the sprite is five columns wide.
DrawLines_FirstPair	53437	POP DE	Draw the first pair of a sprite that has five.
	53438	LD L,E
	53439	AND (HL)
	53440	LD L,D
	53441	XOR (HL)
	53442	CPL
	53443	LD (BC),A
	53444	INC BC
	53445	INC H
	53446	LD L,E
	53447	LD A,(BC)
	53448	AND (HL)
	53449	LD L,D
	53450	XOR (HL)
	53451	CPL
	53452	DEC H
	53453	POP DE	Draw the second pair of a sprite that has four or five.
	53454	LD L,E
	53455	AND (HL)
	53456	LD L,D
	53457	XOR (HL)
	53458	CPL
	53459	LD (BC),A
	53460	INC BC
	53461	INC H
	53462	LD L,E
	53463	LD A,(BC)
	53464	AND (HL)
	53465	LD L,D
	53466	XOR (HL)
	53467	CPL
	53468	DEC H
	53469	POP DE	Draw the third pair of a sprite that has three or more.
	53470	LD L,E
	53471	AND (HL)
	53472	LD L,D
	53473	XOR (HL)
	53474	CPL
	53475	LD (BC),A
	53476	INC BC
	53477	INC H
	53478	LD L,E
	53479	LD A,(BC)
	53480	AND (HL)
	53481	LD L,D
	53482	XOR (HL)
	53483	CPL
	53484	DEC H
	53485	POP DE	Draw the fourth pair of a sprite that has two or more.
	53486	LD L,E
	53487	AND (HL)
	53488	LD L,D
	53489	XOR (HL)
	53490	CPL
	53491	LD (BC),A
	53492	INC BC
	53493	INC H
	53494	LD L,E
	53495	LD A,(BC)
	53496	AND (HL)
	53497	LD L,D
	53498	XOR (HL)
	53499	CPL
	53500	DEC H
	53501	POP DE	Draw the last pair.
	53502	LD L,E
	53503	AND (HL)
	53504	LD L,D
	53505	XOR (HL)
	53506	CPL
	53507	LD (BC),A
	53508	INC BC
	53509	INC H
	53510	LD L,E
	53511	LD A,(BC)
	53512	AND (HL)
	53513	LD L,D
	53514	XOR (HL)
	53515	CPL
	53516	DEC H
	53517	LD (BC),A	Write the last byte of the line.
This entry point is used by the routine at DrawAlignedColumns. Step on to the next line. The aligned columns jump here after their last column.
DrawLines_Next	53518	LD A,C	Fetch C.
DrawLines_Step	53519	ADD A,0	Add the step, which is changed for the width of the sprite.
	53521	LD C,A	Copy it to C.
	53522	LD A,B	Fetch B.
	53523	ADC A,0	Add 0 with carry.
	53525	LD B,A	Copy it to B.
	53526	EX AF,AF'	Fetch A'.
	53527	DEC A	Decrement A.
	53528	JP NZ,DrawLines	Jump to DrawLines if it is not zero.
	53531	LD SP,(23305)	Fetch SavedStackPointer and return.
	53535	RET	Fetch SavedStackPointer and return.
View the equivalent code in; Knight Lore Pentagram