Semigraphics is a mode where alphanumerics and low resolution graphics can be mixed together. The 8th bit of a character determines if it is alphanumeric or treated as a 2 × 2 pixel grid. When the 8th bit is set, the next three bits determine the color and last 4 bits specify which quadrants of the character box are either the selected color or black. This allows a 64 × 32 graphics mode with 9 colors, the only mode where it is possible to display all 9 colors simultaneously.
semigraphics is a mode where alphanumerics and low resolution graphics can be mixed together the 8th bit of a character determines if it is alphanumeric or treated as a 2 × 2 pixel grid when the 8th bit is set the next three bits determine the color and last 4 bits specify which quadrants of the character box are either the selected color or black this allows a 64 × 32 graphics mode with 9 colors the only mode where it is possible to display all 9 colors simultaneously