bit 

 Function 

 2 

 Gouraud shading enable bit 

 1 

 Original picture 1/2 valid bit 

 0 

 Base 1/2 valid bit 

- 

- 

- 

- 

- 

Color Calculation			Underground MSB	Original Picture	Background	Types of Color Operations	Available modes
bit 2	1	0					Original	Background
0	0	0	1	0	replace	Unlimited	Unlimited
0	0	1	0	0	1	Do not rewrite	No restrictions	Unlimited
			1	0 * 1	1/2	shadow		RGB
0	1	0	1/2	0	half luminance	RGB	Unlimited
0	1	1	0	1	0	replace	RGB	Unlimited
			1	1/2	1/2	half translucent		RGB
1	0	0	Gouraud	0	Gouraud shading	RGB	Unlimited
1	0	1	-	-	Setting prohibited (Do not set)	-	-
1	1	0	Golow 1/2	0	Gouraud shading + half brightness * 2	RGB	Limit None
1	1	1	0	Gouraud	0	Gouraud shading	RGB	Unlimited
			1	Golow 1/2	1/2	Gouraud shading + translucent * 3		RGB

[Note]-: Don'tcare 
  Original picture: Pixel data to be drawn with sprite or non-texture 
  Base: Pixel data already drawn in the frame buffer 
  * 1: Refer to the original picture (transparent pixel end code). 
  * 2: After the Gouraud calculation, the data subjected to saturation processing is reduced to 1/2. 
  * 3: After the Gouraud calculation, add the background to the saturated data to make 1/2.