Graphics controller utilizing video memory to provide macro command capability and enhanched command buffering
US5796413A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1995 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Dec 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/39
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method are disclosed for buffering graphics commands in a video graphics system, and for implementing graphics macro commands. The invention makes use of off-screen portions of video memory to create a dynamic command FIFO for commands, and to store command sequences for later or repeated use ("macros"). A command FIFO controller is provided, along with an on-chip bus FIFO and an on-chip command buffer (which is also a FIFO). Several multiplexers are also provided, so as to enable the command FIFO controller to create several different paths for commands coming into the graphics controller. Incoming commands may be routed to the command execution circuitry in several different ways: through the bus FIFO and command buffer to the command execution circuitry, directly to the command execution circuitry by bypassing the bus FIFO and command buffer, or from the bus FIFO into video memory to be stored in a dynamic command FIFO and later retrieved and sent into the command buffer. The command FIFO controller is also provided with macro address generation logic for providing read pointers to macros stored in video memory, read and write address generation logic for access…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.