SEGA SATURN DEVELOPER'S MANUAL

Command table

The command table is a table in which commands are defined on VRAM. VDP1 reads the commands and performs drawing and clipping of parts.
The
command is as follows:

drawing commands:
It is divided into texture drawing and non-texture drawing, and there are regular sprite, rectangular sprite, deformation sprite drawing command, polygon, polyline, line drawing command, and these parts are drawn.
Clipping coordinate setting command:
There are user clipping and system clipping coordinate setting commands to set the drawing area of the part.
Relative coordinate setting command:
Specify to define the drawing coordinates of parts in relative coordinates.
Drawing end command:
Finish drawing.
The command table size is 1EH (30) Byte and the boundary is 20H (32) Byte.
Each command is read into VDP1 and processed individually. This behavior is called fetching.
The command table is fetched from the VRAM start address (000000H), and the next command table is fetched according to the jump format specification.
Color lookup table, Gouraud shading table, and character pattern table are referenced according to the command table specification.