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VDP1 User's Manual/Chapter 6 Command Table

■6.7 CMDXA~CMDYD (vertex coordinate data)

Specify coordinates such as clipping area coordinates and sprite drawing vertex coordinates in CMDXA to CMDYD. Up to 4 vertex coordinates (X coordinate, Y coordinate) can be specified. Define 16 bytes (8 words) from the start address +0CH to +1AH of the command table.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 CMDXA +0CH sign extension Vertex (A), X coordinate (XA) CMDYA +0EH sign extension Vertex (A), Y coordinate (YA) CMDXB +10H sign extension Vertex (B), X coordinate (XB) or display, X width CMDYB +12H sign extension Vertex (B), Y coordinate (YB) or display, Y width CMDXC +14H sign extension Vertex (C), X coordinate (XC) CMDYC +16H sign extension Vertex (C), Y coordinate (YC) CMDXD +18H sign extension Vertex (D), X coordinate (XD) CMDYD +1AH sign extension Vertex (D), Y coordinate (YD)

Specify the coordinates in CMDXA to CMDYD with 16 bits each. Specify negative numbers as two's complement numbers. The specifiable range is -1024 to 1023. The upper 5 bits are sign extended and write the same value as bit 10.
The meanings of CMDXA to CMDYD differ depending on each command. The correspondence between commands and CMDXA to CMDYD is as follows. See each command for details.

Table 6.6 Correspondence between commands and CMDXA to CMDYD

command		CMDXA CMDYA	CMDXB CMDYB	CMDXC CMDYC	CMDXD CMDYD
Standard sprite drawing command		Vertex (A)	−	−	−
Rectangle sprite drawing command (There are two ways)	Specify 2 coordinates	Vertex (A)	−	Vertex (C)	−
Rectangle sprite drawing command (There are two ways)	Fixed point specification	fixed point coordinates	Display width	−	−
Transform sprite drawing commands		Vertex (A)	Vertex (B)	Vertex (C)	Vertex (D)
polygon drawing commands		Vertex (A)	Vertex (B)	Vertex (C)	Vertex (D)
Polyline drawing command		Vertex (A)	Vertex (B)	Vertex (C)	Vertex (D)
Line drawing command		Vertex (A)	Vertex (B)	−	−
User clipping coordinate setting command		top left coordinate	−	lower right coordinate	−
System clipping coordinate setting command		−	−	lower right coordinate	−
Relative coordinate setting command		relative coordinates	−	−	−

[Note] - is not used.

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	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
CMDXA +0CH	sign extension					Vertex (A), X coordinate (XA)
CMDYA +0EH	sign extension					Vertex (A), Y coordinate (YA)
CMDXB +10H	sign extension					Vertex (B), X coordinate (XB) or display, X width
CMDYB +12H	sign extension					Vertex (B), Y coordinate (YB) or display, Y width
CMDXC +14H	sign extension					Vertex (C), X coordinate (XC)
CMDYC +16H	sign extension					Vertex (C), Y coordinate (YC)
CMDXD +18H	sign extension					Vertex (D), X coordinate (XD)
CMDYD +1AH	sign extension					Vertex (D), Y coordinate (YD)