Return to previous page | Return to menu | Go to next page
-
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.
Return to previous page | Return to menu | Go to next page