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VDP1 User's Manual / Chapter 6 Command Table

■ 6.7 CMDXA ~ CMDYD (vertex coordinate data)

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

15 14 13 12 11 Ten 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)

The coordinates are 16 bits each and are specified in CMDXA to CMDYD. Negative numbers are specified in 2's complement. The range is -1024 to 1023. The upper 5 bits are sign-extended and write the same value as bit 10.
The meaning of CMDXA to CMDYD differs depending on each command. The correspondence between the command and CMDXA to CMDYD is as follows. For details, refer to each command.

Table 6.6 Correspondence between commands and CMDXA to CMDYD

command		CMDXA CMDYA	CMDXB CMDYB	CMDXC CMDYC	CMDXD CMDYD
Fixed 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 designation	Fixed point coordinates	Display width	−	−
Transform sprite drawing command		Vertex (A)	Vertex (B)	Vertex (C)	Vertex (D)
Polygon drawing command		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		Upper left coordinates	−	Lower right coordinates	−
System clipping coordinate setting command		−	−	Lower right coordinates	−
Relative coordinate setting command		Relative coordinates	−	−	−

[Note]-is unused.

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