bit	Function
2	Gouraud shading enable bit
1	Original picture 1/2 valid bit
0	Base 1/2 valid bit

色 Color calculation is performed on the drawn sprite or non-texture pixel data and the pixel data already drawn in the frame buffer.
以外 The color code of the original picture is valid only when the RGB code is used, except for replace and shadow color calculations. Color calculation can also be performed for color bank codes, but the results are not guaranteed.
∙ For sprites, color calculation is possible when the color mode is mode 1 (lookup table mode) and the color code of the color lookup table is RGB code, or mode 5 (RGB mode). When non-texture, color calculation is possible when non-texture color is RGB code.
In the color calculation of the part with the original picture, the transparent code is valid when SPD = 0 and the end code is valid when ECD = 0, and color calculation is not performed for those pixels.
∙ Color calculation for polygons, polylines, and lines is valid only when the non-texture color is RGB code.
∙ Color calculation is not possible at 8bit / pixel (high resolution or rotation 8).