Video/graphics controller which performs pointer-based display list video refresh operation

• US 6,067,098 A
• Filed: 04/06/1998
• Issued: 05/23/2000
• Est. Priority Date: 11/16/1994
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures I LLC (Intellectual Ventures LLC)
• Original Assignee: Interactive Silicon, Inc.
• Inventors: Dye, Thomas A.
• Primary Examiner(s): Chauhan, Ulka J.
• Application Number:
  US09/056,021
• Time in Patent Office: 778 Days
• Field of Search: 345/501-503, 345/520, 345/521, 345/507, 345/509, 345/515, 345/516
• US Class Current: 345/531
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 2212/401 Compressed data
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2360/121 using a cache memory
• CPC Class Codes: G09G 5/14 Display of multiple viewports
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory
• CPC Class Codes: G09G 5/42 characterised by the display of patterns using a display memory without fixed position correspondence between the display memory contents and the display position on the screen

Abstract

A graphics controller (IMC) which performs pointer-based and/or display list-based video refresh operations that enable screen refresh data to be assembled on a per window or per object basis, thereby greatly increasing the performance of the graphical display. The graphics controller maintains pointers to various buffers in system memory comprising video or graphics display information. The graphics controller manipulates respective object information workspace memory areas corresponding to each object or window, wherein the workspace areas specify data types, color depths, 3D depth values, alpha blending information, screen position, etc. for the respective window or object on the screen. Each workspace area also includes static and dynamic pointers which point to the location in system memory where the pixel data for the respective window or object is stored. The graphics controller utilizes this information, as well as information received from the software driver regarding screen changes, to assemble a display refresh list in system memory. This information is used during the screen refresh to display the various windows or objects on the screen very quickly and efficiently. Thus, the video display can be updated with new video data without requiring any system bus data transfers, which are required in prior art computer system architectures. The graphics controller dynamically adjusts the display refresh list for movement of objects and changes in relative depth priority which appear on the display. Thus the video data for the various windows and objects is stored in respective memory areas in the system memory, and pointers assembled in the display refresh list are used to reference this data during screen updates. Therefore, data is not required to be moved in or out of a frame buffer to reflect screen changes. Rather, in many instances, either the video data for a respective window or object is changed, or only the pointers in the display refresh list are manipulated, to affect a screen change.

Claims

1. A system including a graphics controller which performs display functions, comprising:

a CPU;

a display device including one or more video inputs for receiving video signals and including a display screen for displaying video output, wherein the display screen of the display device displays video output in response to video signals received at said one or more video inputs;

memory coupled to the CPU which stores video data, wherein the memory stores video data in a plurality of memory areas; and

a graphics controller coupled to said CPU, said memory, and said display device, wherein said graphics controller obtains portions of said video data from said plurality of memory areas in said memory and in response provides video signals to said display device;

wherein said graphics controller maintains a display list comprising a plurality of pointers which point to at least portions of said video data in one or more of said plurality of memory areas in said memory;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain said at least portions of said video data from said one or more of said plurality of memory areas in said memory;

wherein said graphics controller provides said video signals to said display device in response to said graphics controller obtaining said at least portions of said video data from said one or more of said plurality of memory areas in said memory.

2. The system of claim 1, wherein said display screen of said display device is adapted to display a plurality of video objects;

wherein said plurality of memory areas store video data for a plurality of video objects, wherein each of said memory areas stores video data corresponding to a video object;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain said at least portions of said video data for each of said plurality of video objects.

3. The system of claim 1, wherein said display device displays data on said display screen using a plurality of scan lines;

wherein said plurality of pointers comprising said display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said graphics controller uses said plurality of pointers in said order to obtain video data from said plurality of memory areas in said memory for respective scan lines as said scan lines are drawn on the display screen of said display device.

4. The system of claim 3, wherein at least one of said plurality of scan lines comprised on said display device displays video data corresponding to a first plurality of objects from a first plurality of memory areas;

wherein said plurality of pointers comprising said display list include a first plurality of pointers corresponding to said at least one of said plurality of scan lines, wherein said first plurality of pointers reference video data portions from said first plurality of memory areas corresponding to said first plurality of objects;

wherein said graphics controller uses said first plurality of pointers to obtain said video data portions from said first plurality of memory areas for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

5. The system of claim 4, wherein said first plurality of objects appear in a first order from left to right across said at least one of said plurality of scan lines comprised on said display device;

wherein said first plurality of pointers include a first order corresponding to said first order of said first plurality of objects;

wherein said first plurality of pointers are accessed in said first order to obtain said video data from said memory corresponding to said first plurality of objects;

wherein said first plurality of objects are displayed on said at least one of said plurality of scan lines in said first order.

6. The system of claim 5, wherein said display list further comprises video data amount information indicating an amount of each of said video data portions obtained from said first plurality of memory areas corresponding to said first plurality of objects;

wherein said graphics controller uses said video data amount information with said first plurality of pointers to obtain amounts of each of said video data portions from said first plurality of memory areas for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

7. The system of claim 3, wherein said display screen of said display device displays a first video object comprising at least portions of a first plurality of scan lines comprised on said display device;

wherein said memory includes a first memory area storing video data corresponding to said first video object;

wherein said plurality of pointers comprising said display list include a first plurality of pointers which reference video data portions from said first memory area corresponding to said first object;

wherein said first plurality of pointers reference video data portions of said first object corresponding to said at least portions of said first plurality of scan lines;

wherein said graphics controller uses said first plurality of pointers to obtain said video data portions from said first memory area for said plurality of scan lines when said scan lines are drawn on the display screen.

8. The system of claim 1, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein, in response to said video display information, said graphics controller assembles a new display list to effect desired changes on said video output of said display device, wherein said new display list comprises a second plurality of pointers;

wherein said graphics controller uses said second plurality of pointers in said new display list to read portions of said video data from said plurality of memory areas in said memory and provide video signals to said display device according to said desired changes to said display device.

9. The system of claim 8, wherein said display device displays data using a plurality of scan lines;

wherein said second plurality of pointers comprising said new display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said graphics controller uses said second plurality of pointers in said order to obtain video data from said memory for respective scan lines as said scan lines are drawn on the display screen.

10. The system of claim 8, wherein a video driver executing on said CPU provides said video display information to said graphics controller.

11. The system of claim 1, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein, in response to said video display information, said graphics controller manipulates one or more of said plurality of pointers in said display list to effect desired changes on said video output of said display device;

wherein said graphics controller uses said manipulated plurality of pointers in said display list to read portions of said video data from said plurality of memory areas in said memory and provide said video signals to said display device according to said desired changes to said display device.

12. The system of claim 1, wherein said display device displays a plurality of objects;

wherein said graphics controller maintains a plurality of object information areas in said memory which each correspond to a respective one of said objects appearing on said display device, wherein said plurality of object information areas comprise information regarding said objects displayed on said display device;

wherein said graphics controller uses said information in said object information areas to assemble said display list.

13. The system of claim 12, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein, in response to said video display information, said graphics controller manipulates information in one or more of said object information areas;

wherein said graphics controller uses said manipulated information in said one or more object information areas to assemble said display list.

14. The system of claim 13, wherein said one or more object information areas include workspace areas which correspond to respective objects on said display device;

wherein each of said one or more workspace areas comprises location information including an x,y location of a respective object appearing on said display device.

15. The system of claim 14, wherein each of said one or more workspace areas comprises information indicating a number of bits per pixel, one or more depth bits and one or more alpha blending bits.

16. The system of claim 14, wherein each of said one or more workspace areas further includes a static address pointer which points to an area in said system memory storing video data for a respective object, and a dynamic linear address pointer which points video data portions in said areas of system memory which correspond to horizontal scan lines on said display device, wherein said dynamic linear address pointer is used to increment through horizontal scan lines of said object pointed to by said static pointer.

17. The system of claim 14, wherein said one or more object information areas include an ID list comprising pointer entries which each correspond to a video object on said display device;

wherein each of said ID list pointer entries point to respective ones of said one or more workspace areas in said system memory.

18. The system of claim 13, wherein said display device displays a plurality of windows including a first window and a second window, wherein the second window at least partially overlaps the first window, wherein the second window is initially behind the first window in relative depth such that a portion of said second window is occluded, wherein the user selects the second window so that the second window becomes in front of the first window in relative depth;

wherein the graphics controller receives video display information indicating that the second window should be in front of the first window;

wherein, in response to said video display information, said graphics controller manipulates information in one or more of said object information areas to indicate that the second window has a higher relative depth priority than the first window;

wherein said graphics controller uses said manipulated information in said one or more object information areas to assemble said display list;

wherein said graphics controller uses said display list to present video data to said display device such that said display device displays said second window in front of said first window, wherein a portion of said first window is occluded.

19. The system of claim 18, wherein said video data in said memory corresponding to said first window and said video data in said memory corresponding to said second window are not moved in said memory.

20. The system of claim 13, wherein said display device displays a plurality of windows including a first window, wherein the user moves the first window to a new location;

wherein the graphics controller receives video display information indicating that the first window should be moved to a new location;

wherein, in response to said video display information, said graphics controller manipulates information in one or more of said object information areas to indicate that the first window has moved to a new location;

wherein said graphics controller uses said manipulated information in said one or more object information areas to assemble said display list;

wherein said graphics controller uses said display list to present video data to said display device such that said display device displays said first window at said new location.

21. The system of claim 20, wherein said video data in said memory corresponding to said first window is not moved in said memory.

22. The system of claim 1, wherein said graphics controller maintains a foreground display list of address pointers and a background display list of address pointers, wherein each of said foreground and background display lists point to respective areas in said system memory storing video data;

wherein said graphics controller alternates use of said foreground display list and background display list to provide said video signals to said display device during screen refresh.

23. The system of claim 1, wherein said graphics controller includes an execution engine which assembles said display list comprising said plurality of pointers;

wherein said graphics controller further includes a display list refresh engine which uses said plurality of pointers in said display list to read portions of said video data and provide said video signals to said display device.

24. The system of claim 23, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein said execution engine assembles a new display list comprising a second plurality of pointers in response to receiving said video display information;

wherein said display list refresh engine uses said second plurality of pointers in said new display list to read portions of said video data and provide said video signals to said display device according to said desired changes to said video output of said display device.

25. The system of claim 23, wherein said execution engine includes:

means for receiving an assemble display list command;

means for sorting Y values in said one or more windows workspace areas;

means for sorting horizontal X values for each of said sorted Y values in said windows workspace area; and

means for assembling pointers in said display list which reference video data in said memory, wherein said means for assembling assembles said pointers in said display list corresponding to scan lines on said display device.

26. The system of claim 1, wherein said graphics controller includes one or more video ports for providing video signals directly to said display device.

27. The system of claim 1, wherein said memory is system memory which stores code and data used by said CPU for executing one or more applications.

28. The system of claim 1, wherein the display device comprises a computer video monitor.

29. The system of claim 1, wherein the system comprises a television system, and wherein the display device includes a television screen.

30. The system of claim 29, wherein the system comprises a television system and a set top box connected to the television system;

wherein the set top box includes two or more of the CPU, the memory, and the graphics controller;

wherein the television system comprises the display device.

31. A memory system for storing video data that is output to a display device, said memory system comprising:

memory including a plurality of display memory areas for storing video data for a plurality of video objects, said memory also including an object workspace memory area including attributes for each of said video objects in said display memory area; and

a memory controller coupled to said memory, wherein said memory controller comprises;

an execution engine which receives display change information and which assembles a display list comprising a plurality of pointers, wherein said execution engine uses said attributes in said object workspace memory area in assembling said display list, wherein said display list includes said plurality of pointers for accessing said video data for said one or more video objects within said display memory area for display on the display device; and

a display refresh list engine which uses said plurality of pointers comprising said display list for accessing said video data stored in said display memory area and for providing video signals to the display device.

32. The memory system of claim 31, wherein said plurality of pointers are ordered in said display list to access said video data for said plurality of video objects within said display memory area as said video objects are displayed in horizontal scan lines on the display device.

33. The memory system of claim 31, wherein the memory system stores video data that is output to a display device, wherein the display device includes a display screen and displays data on the display screen using a plurality of scan lines;

wherein said plurality of pointers comprising said display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said memory controller uses said plurality of pointers in said order to obtain video data from said plurality of display memory areas in said memory for respective scan lines as said scan lines are drawn on the display screen of the display device.

34. The memory system of claim 31, wherein said display refresh list engine operates during screen refresh to access said pointers in said display list and to retrieve corresponding pixel data for display on the display device.

35. The memory system of claim 31, wherein said attributes in said workspace memory area for each of said objects include XY addresses, pixel color information, a static pointer pointing to the beginning of the pixel data for said one or more video objects and a dynamic pointer for pointing to consecutive scan lines comprising each said video object within said display memory areas.

36. A memory controller for performing memory control and video functions, comprising:

one or more memory controllers adapted for coupling to memory for controlling functions of the memory;

an execution engine which is adapted to maintain a plurality of pointers in memory which reference video data corresponding to video objects, wherein said execution engine receives display change information and assembles a display list comprising said plurality of pointers; and

a display refresh list engine which uses said plurality of pointers comprising said display list for accessing video data stored in memory and for providing video signals to the display device.

37. A method for displaying video data on a display screen of a display device, wherein the display screen comprises a plurality of scan lines presenting video images, the method comprising:

storing video data in a plurality of different memory areas in a memory for a plurality of objects which appear on said display screen;

maintaining a display list of pointers which reference video data in said plurality of different memory areas for said plurality of objects, wherein said pointers are ordered in said display list to reference said video data for respective scan lines on said display screen as said scan lines are drawn on said display screen; and

executing said display list to present said video data on the display screen, wherein said executing comprises using said pointers to access said video data in said plurality of different memory areas in said memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display device for display on said display screen in response to said accessed video data.

38. The method of claim 37, wherein at least one of said plurality of scan lines comprised on said display device displays video data corresponding to a first plurality of objects from a first plurality of memory areas;

wherein said maintaining said display list of pointers includes maintaining a first plurality of pointers corresponding to said at least one of said plurality of scan lines, wherein said first plurality of pointers reference video data portions from said first plurality of memory areas corresponding to said first plurality of objects;

wherein said executing said display list includes using said first plurality of pointers to obtain said video data portions from said first plurality of memory areas for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

39. The method of claim 38, wherein said first plurality of objects appear in a first order from left to right across said at least one of said plurality of scan lines comprised on said display device;

wherein said maintaining said display list of pointers includes maintaining said first plurality of pointers in a first order corresponding to said first order of said first plurality of objects;

wherein said executing said display list includes accessing said first plurality of pointers in said first order to obtain said video data from said memory corresponding to said first plurality of objects;

wherein said first plurality of objects are displayed on said at least one of said plurality of scan lines in said first order.

40. The method of claim 39, wherein said maintaining said display list of pointers includes maintaining video data amount information indicating an amount of each of said video data portions obtained from said first plurality of memory areas corresponding to said first plurality of objects;

wherein said executing said display list includes using said video data amount information with said first plurality of pointers to obtain amounts of each of said video data portions from said first plurality of memory areas for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

41. The method of claim 37, wherein said display screen of said display device displays a first video object comprising at least portions of a first plurality of scan lines comprised on said display device;

wherein said memory includes a first memory area storing video data corresponding to said first video object;

wherein said maintaining said display list of pointers includes maintaining a first plurality of pointers which reference video data portions from said first memory area corresponding to said first object;

wherein said first plurality of pointers reference video data portions of said first object corresponding to said at least portions of said first plurality of scan lines;

wherein said executing said display list includes using said first plurality of pointers to obtain said video data portions from said first memory area for said plurality of scan lines when said scan lines are drawn on the display screen.

42. The method of claim 37, further comprising:

receiving video display change information indicating a desired display change on the display screen;

manipulating said pointers in said display list to produce an updated display list according to said desired change on the display screen; and

executing said updated display list to present said video data on the display screen according to said desired display changes, wherein said executing comprises using said manipulated pointers to access said video data in memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display screen in response to said accessed video data.

43. The method of claim 37, further comprising:

receiving video display change information indicating a desired display change on the display screen;

assembling a new display list comprising a second plurality of pointers according to said desired change on the display screen; and

executing said new display list to present said video data on the display screen according to said desired display changes, wherein said executing comprises using said second plurality of pointers to access said video data in memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display screen in response to said accessed video data.

44. The method of claim 37, wherein said executing said display list is performed on each screen refresh.

45. The method of claim 37, further comprising

maintaining a plurality of object information areas in said system memory which each correspond to a respective one of said objects appearing on said display device, wherein said plurality of object information areas comprise information regarding said objects displayed on said display device;

wherein said maintaining said display list of pointers includes using said information in said object information areas to assemble said display list.

46. The method of claim 45, further comprising:

receiving video display information regarding desired changes to said video output of said display device;

manipulating information in one or more of said object information areas in response to receiving said video display information;

wherein said maintaining said display list of pointers includes using said manipulated information in said one or more object information areas to assemble said display list.

47. The method of claim 45, wherein said maintaining said plurality of object information areas in said system memory includes maintaining workspace areas which correspond to respective objects on said display device;

wherein each of said one or more workspace areas comprises location information including an x,y location of a respective object appearing on said display device.

48. The method of claim 47, wherein said maintaining said plurality of object information areas in said system memory includes maintaining workspace areas which comprise information indicating a number of bits per pixel, one or more depth bits and one or more alpha blending bits.

49. The method of claim 47, wherein said maintaining said plurality of object information areas in said system memory includes maintaining workspace areas which further include a static address pointer which points to an area in said system memory storing video data for a respective object, and a dynamic linear address pointer which points video data portions in said areas of system memory which correspond to horizontal scan lines on said display device, wherein executing said display list includes using said dynamic linear address pointer to increment through horizontal scan lines of said object pointed to by said static pointer.

50. The method of claim 45, wherein said maintaining said plurality of object information areas in said system memory includes maintaining an ID list comprising pointer entries which each correspond to a video object on said display device;

wherein each of said ID list pointer entries point to respective ones of said one or more workspace areas in said system memory, wherein said one or more pointers in said windows ID list correspond to said objects appearing on said display device.

51. The method of claim 37, further comprising:

maintaining a plurality of workspace areas corresponding to said plurality of objects, wherein each of said one or more workspace areas comprise information for its respective object, including location coordinates for said object on the display screen, color composition information, depth information, and one or more pointers to video data of the object;

wherein said maintaining said display list comprises assembling said display list using information in said plurality of workspace areas.

52. The method of claim 51, wherein said assembling said display list comprises:

obtaining said location coordinates in said workspace area for each of said objects;

sorting said location coordinates for each scan line of said display screen;

assembling pointers in said display list which reference said video data in response to said step of sorting.

53. The method of claim 51, wherein said location coordinates in each of said workspace areas comprise X and Y coordinates;

wherein said step of assembling said display list further comprises;

obtaining said location coordinates in said workspace areas for each of said objects;

sorting said Y coordinates of said location coordinates for each scan line of said display screen;

sorting said X coordinates of said location coordinates across a scan line;

comparing the depth information of objects on said scan line to determine relative depth of said objects in said scan line;

assembling pointers in said display list which reference said video data for said scan line; and

performing said steps of sorting said X coordinates comparing the depth information, and assembling pointers for each of said scan lines.

54. The method of claim 53, wherein said step of assembling pointers in said display list comprises assembling said pointers which reference video data for said objects as said objects appear left to right on said scan lines.

55. The method of claim 54, further comprising:

storing pitch values in said display list indicating an amount of pixel data corresponding to a width of said object on said scan line.

56. The method of claim 53, further comprising:

determining if assembled pointers for a scan line are equal to assembled pointers for the immediately prior scan line after said step of assembling;

storing a repeat count value in said display list for said scan line if said assembled pointers for said scan line are equal to said assembled pointers for the immediately prior scan line.

57. The method of claim 45, further comprising:

the display device displaying a plurality of windows including a first window and a second window, wherein the second window at least partially overlaps the first window, wherein the second window is initially behind the first window in relative depth such that a portion of said second window is occluded;

a user selecting the second window to enable the second window to become in front of the first window in relative depth;

receiving video display information indicating that the second window should be in front of the first window;

manipulating information in one or more of said object information areas to indicate that the second window has a higher relative depth priority than the first window, wherein said manipulating information in one or more of said object information areas to indicate that the second window has a higher relative depth priority than the first window is performed in response to receiving said video display information;

wherein said maintaining said display list of pointers includes using said manipulated information in said one or more object information areas to assemble said display list;

wherein said executing said display list includes using said display list to present video data to said display device such that said display device displays said second window in front of said first window, wherein a portion of said first window is occluded.

58. The method of claim 57, wherein said video data in said memory corresponding to said first window and said video data in said memory corresponding to said second window are not moved in said memory.

59. The method of claim 45, further comprising:

the display device displaying a plurality of windows including a first window;

a user performing an action to effect moving the first window to a new location;

receiving video display information indicating that the first window should be moved to a new location;

manipulating information in one or more of said object information areas to indicate that the first window has moved to a new location, wherein said manipulating information in one or more of said object information areas to indicate that the first window has moved to a new location is performed in response to receiving said video display information;

wherein said maintaining said display list of pointers includes using said manipulated information in said one or more object information areas to assemble said display list;

wherein said executing said display list includes using said display list to present video data to said display device such that said display device displays said first window at said new location.

60. The method of claim 59, wherein said video data in said memory corresponding to said first window is not moved in said memory.

61. The method of claim 45, further comprising:

the memory storing video data corresponding to a first window;

the display device displaying only a first portion of said first window;

a user performing an action to effect panning to view a second portion of the first window;

receiving video display information indicating that the first window should be panned to display a second portion of the first window;

manipulating information in one or more of said object information areas to indicate that the first window should be panned to display a second portion of the first window, wherein said manipulating information in one or more of said object information areas to indicate that the first window has moved to a new location is performed in response to receiving said video display information;

wherein said maintaining said display list of pointers includes using said manipulated information in said one or more object information areas to assemble said display list;

wherein said executing said display list includes using said display list to present video data to said display device such that said display device displays said second portion of said first window.

62. The method of claim 61, wherein said video data in said memory corresponding to said first window is not moved in said memory.

63. The method of claim 37, wherein said maintaining said display list comprises:

receiving an assemble display refresh list command indicating only one object is to be changed on the screen;

assembling pointers in said display list for only said one object.

64. The method of claim 37, wherein said executing said display list is performed during screen refresh.

65. The method of claim 64, wherein, for each of said scan lines on the display screen, said executing said display list comprises:

obtaining said pointers in said display list for a scan line of the display screen; and

obtaining said video data referenced by said pointers for said scan line of the display screen for presentation on the display screen.

66. The method of claim 37, wherein said storing said video include storing video data having a different number of bits per pixel for different objects;

wherein said executing comprises transferring data on a data path having different data widths according to said different numbers of bits per pixel of said video data for respective objects.

67. The method of claim 66, wherein video data for a first object has a first number of bits per pixel and video data for a second object has a second number of bits per pixel;

wherein said transferring comprises dynamically reconfiguring said data path according to said first number of bits per pixel when said video data for said first object is being transferred; and

wherein said transferring comprises dynamically reconfiguring said data path according to said second number of bits per pixel when said video data for said second object is being transferred.

68. A system including a graphics controller which performs video functions, comprising:

a CPU;

a display device for displaying video output;

memory coupled to the CPU which stores video data, wherein the memory includes a plurality of memory areas storing video data for a plurality of objects; and

a graphics controller coupled to said CPU, said memory, and said display device which performs video functions, wherein said graphics controller obtains said video data in said memory and provides video signals to said display device;

wherein said graphics controller maintains a display list comprising a plurality of pointers which point to plurality of different areas in said memory storing said video data;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain video data from said memory and provide said video signals to said display device.

69. A system including a graphics controller which performs display functions, comprising:

a display device including one or more video inputs for receiving video signals and including a display screen for displaying video output, wherein the display screen of the display device displays video output in response to video signals received at said one or more video inputs;

memory which stores video data; and

a graphics controller coupled to said memory and said display device, wherein said graphics controller obtains portions of said video data from said memory and in response provides video signals to said display device;

wherein said graphics controller maintains a display list comprising a plurality of pointers which point to at least portions of said video data in said memory;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain said at least portions of said video data from said memory;

wherein said graphics controller provides said video signals to said display device in response to said graphics controller obtaining said at least portions of said video data from said memory.

70. The system of claim 69,

wherein the memory stores video data in a plurality of memory areas;

wherein said graphics controller obtains portions of said video data from one or more of said plurality of memory areas in said memory and in response provides video signals to said display device;

wherein said display list comprises a plurality of pointers which point to at least portions of said video data in one or more of said plurality of memory areas in said memory;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain said at least portions of said video data from said one or more of said plurality of memory areas in said memory;

wherein said graphics controller provides said video signals to said display device in response to said graphics controller obtaining said at least portions of said video data from said one or more of said plurality of memory areas in said memory.

71. The system of claim 69, wherein said display screen of said display device is adapted to display a plurality of video objects;

wherein said memory stores video data for a plurality of video objects;

wherein said graphics controller uses said plurality of pointers comprised in said display list to obtain said at least portions of said video data for each of said plurality of video objects.

72. The system of claim 69, wherein said display device displays data on said display screen using a plurality of scan lines;

wherein said plurality of pointers comprising said display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said graphics controller uses said plurality of pointers in said order to obtain video data from said memory for respective scan lines as said scan lines are drawn on the display screen of said display device.

73. The system of claim 72, wherein at least one of said plurality of scan lines comprised on said display device displays video data corresponding to a first plurality of objects;

wherein said plurality of pointers comprising said display list include a first plurality of pointers corresponding to said at least one of said plurality of scan lines, wherein said first plurality of pointers reference video data portions from said memory corresponding to said first plurality of objects;

wherein said graphics controller uses said first plurality of pointers to obtain said video data portions from said memory for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

74. The system of claim 73, wherein said first plurality of objects appear in a first order from left to right across said at least one of said plurality of scan lines comprised on said display device;

wherein said first plurality of pointers include a first order corresponding to said first order of said first plurality of objects;

wherein said first plurality of pointers are accessed in said first order to obtain said video data from said memory corresponding to said first plurality of objects;

wherein said first plurality of objects are displayed on said at least one of said plurality of scan lines in said first order.

75. The system of claim 74, wherein said display list further comprises video data amount information indicating an amount of each of said video data portions obtained from said memory corresponding to said first plurality of objects;

wherein said graphics controller uses said video data amount information with said first plurality of pointers to obtain amounts of each of said video data portions from said memory for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

76. The system of claim 71, wherein said display screen of said display device displays a first video object comprising at least portions of a first plurality of scan lines comprised on said display device;

wherein said memory stores video data corresponding to said first video object;

wherein said plurality of pointers comprising said display list include a first plurality of pointers which reference video data portions from said memory corresponding to said first object;

wherein said first plurality of pointers reference video data portions of said first object corresponding to said at least portions of said first plurality of scan lines;

wherein said graphics controller uses said first plurality of pointers to obtain said video data portions from said memory for said plurality of scan lines when said scan lines are drawn on the display screen.

77. The system of claim 69, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein, in response to said video display in formation, said graphics controller assembles a new display list to effect desired changes on said video output of said display device, wherein said new display list comprises a second plurality of pointers;

wherein said graphics controller uses said second plurality of pointers in said new display list to read portions of said video data from said memory and provide video signals to said display device according to said desired changes to said display device.

78. The system of claim 77, wherein said display device displays data using a plurality of scan lines;

wherein said second plurality of pointers comprising said new display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said graphics controller uses said second plurality of pointers in said order to obtain video data from said memory for respective scan lines as said scan lines are drawn on the display screen.

79. The system of claim 77, wherein a video driver executing on said CPU provides said video display information to said graphics controller.

80. The system of claim 69, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video output of said display device;

wherein, in response to said video display information, said graphics controller manipulates one or more of said plurality of pointers in said display list to effect desired changes on said video output of said display device;

wherein said graphics controller uses said manipulated plurality of pointers in said display list to read portions of said video data from said memory and provide said video signals to said display device according to said desired changes to said display device.

81. The system of claim 69, wherein said display device displays a plurality of objects;

wherein said graphics controller maintains a plurality of object information areas in said memory which each correspond to a respective one of said objects appearing on said display device, wherein said plurality of object information areas comprise information regarding said objects displayed on said display device;

wherein said graphics controller uses said information in said object information areas to assemble said display list.

82. The system of claim 81, wherein said graphics controller includes an input for receiving video display information regarding desired changes to said video out put of said display device;

wherein, in response to said video display information, said graphics controller manipulates information in one or more of said object information areas;

wherein said graphics controller uses said manipulated information in said one or more object information areas to assemble said display list.

83. The system of claim 82, wherein said one or more object information areas include workspace areas which correspond to respective objects on said display device;

wherein each of said one or more workspace areas comprises location information including an x,y location of a respective object appearing on said display device.

84. The system of claim 83, wherein each of said one or more workspace areas comprises information indicating a number of bits per pixel, one or more depth bits and one or more alpha blending bits.

85. The system of claim 69, wherein said graphics controller includes one or more video ports for providing video signals directly to said display device.

86. The system of claim 69, wherein said memory is system memory which stores code and data used by said CPU for executing one or more applications.

87. The system of claim 69, wherein the display device comprises a computer video monitor.

88. The system of claim 69, wherein the system comprises a television system, and wherein the display device includes a television screen.

89. The system of claim 88, wherein the system comprises a television system and a set top box connected to the television system;

wherein the set top box includes two or more of the CPU, the memory, and the graphics controller;

wherein the television system comprises the display device.

90. The system of claim 69, further comprising:

a CPU coupled to said memory and said graphics controller;

wherein the CPU controls operations of the graphics controller.

91. The system of claim 90, wherein the memory stores program instructions, and wherein the CPU executes program instructions from the memory.

92. A memory system for storing video data that is output to a display device, said memory system comprising:

memory for storing video data for a plurality of video objects, said memory also including an object workspace memory area including attributes for each of said video objects; and

a memory controller coupled to said memory, wherein said memory controller comprises;

an execution engine which receives display change information and which assembles a display list comprising a plurality of pointers, wherein said execution engine uses said attributes in said object workspace memory area in assembling said display list, wherein said display list includes said plurality of pointers for accessing said video data for said one or more video objects within said memory for display on the display device; and

a display refresh list engine which uses said plurality of pointers comprising said display list for accessing said video data stored in said memory and for providing video signals to the display device.

93. The memory system of claim 92, wherein said plurality of pointers are ordered in said display list to access said video data for said plurality of video objects within said memory as said video objects are displayed in horizontal scan lines on the display device.

94. The memory system of claim 92, wherein the memory system stores video data that is output to a display device, wherein the display device includes a display screen and displays data on the display screen using a plurality of scan lines;

wherein said plurality of pointers comprising said display list are ordered according to how said video data referenced by said pointers appears on respective scan lines as said scan lines are drawn on the display screen;

wherein said memory controller uses said plurality of pointers in said order to obtain video data from said memory for respective scan lines as said scan lines are drawn on the display screen of the display device.

95. The memory system of claim 92, wherein said display refresh list engine operates during screen refresh to access said pointers in said display list and to retrieve corresponding pixel data for display on the display device.

96. The memory system of claim 92, wherein said attributes in said workspace memory area for each of said objects include XY addresses, pixel color information, a static pointer pointing to the beginning of the pixel data for said one or more video objects and a dynamic pointer for pointing to consecutive scan lines comprising each said video object within said display memory areas.

97. A method for displaying video data on a display screen of a display device, wherein the display screen comprises a plurality of scan lines presenting video images, the method comprising:

storing video data in a memory for a plurality of objects which appear on said display screen;

maintaining a display list of pointers which reference video data in said memory for said plurality of objects, wherein said pointers are ordered in said display list to reference said video data for respective scan lines on said display screen as said scan lines are drawn on said display screen; and

executing said display list to present said video data on the display screen, wherein said executing comprises using said pointers to access said video data in said memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display device for display on said display screen in response to said accessed video data.

98. The method of claim 97, wherein at least one of said plurality of scan lines comprised on said display device displays video data corresponding to a first plurality of objects;

wherein said maintaining said display list of pointers includes maintaining a first plurality of pointers corresponding to said at least one of said plurality of scan lines, wherein said first plurality of pointers reference video data portions from said memory corresponding to said first plurality of objects;

wherein said executing said display list includes using said first plurality of pointers to obtain said video data portions from said memory for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

99. The method of claim 98, wherein said first plurality of objects appear in a first order from left to right across said at least one of said plurality of scan lines comprised on said display device;

wherein said maintaining said display list of pointers includes maintaining said first plurality of pointers in a first order corresponding to said first order of said first plurality of objects;

wherein said executing said display list includes accessing said first plurality of pointers in said first order to obtain said video data from said memory corresponding to said first plurality of objects;

wherein said first plurality of objects are displayed on said at least one of said plurality of scan lines in said first order.

100. The method of claim 99, wherein said maintaining said display list of pointers includes maintaining video data amount information indicating an amount of each of said video data portions obtained from said memory corresponding to said first plurality of objects;

wherein said executing said display list includes using said video data amount information with said first plurality of pointers to obtain amounts of each of said video data portions from said memory for said at least one of said plurality of scan lines when said scan line is drawn on the display screen.

101. The method of claim 97, wherein said display screen of said display device displays a first video object comprising at least portions of a first plurality of scan lines comprised on said display device;

wherein said memory stores video data corresponding to said first video object;

wherein said maintaining said display list of pointers includes maintaining a first plurality of pointers which reference video data portions from said memory corresponding to said first object;

wherein said first plurality of pointers reference video data portions of said first object corresponding to said at least portions of said first plurality of scan lines;

wherein said executing said display list includes using said first plurality of pointers to obtain said video data portions from said memory for said plurality of scan lines when said scan line s are drawn on the display screen.

102. The method of claim 97, further comprising:

receiving video display change information indicating a desired display change on the display screen;

manipulating said pointers in said display list to produce an updated display list according to said desired change on the display screen; and

executing said updated display list to present said video data on the display screen according to said desired display changes, wherein said executing comprises using said manipulated pointers to access said video data in said memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display screen in response to said accessed video data.

103. The method of claim 97, further comprising:

receiving video display change information indicating a desired display change on the display screen;

assembling a new display list comprising a second plurality of pointers according to said desired change on the display screen; and

executing said new display list to present said video data on the display screen according to said desired display changes, wherein said executing comprises using said second plurality of pointers to access said video data in said memory for respective scan lines as said scan lines are drawn on the display screen, wherein said executing further comprises generating video signals to said display screen in response to said accessed video data.

104. The method of claim 97, further comprising

maintaining a plurality of object information areas in said system memory which each correspond to a respective one of said objects appearing on said display device, wherein said plurality of object information areas comprise information regarding said objects displayed on said display device;

wherein said maintaining said display list of pointers includes using said information in said object information areas to assemble said display list.

105. The method of claim 104, further comprising:

receiving video display information regarding desired changes to said video output of said display device;

manipulating information in one or more of said object information areas in response to receiving said video display information;

wherein said maintaining said display list of pointers includes using said manipulated information in said one or more object information areas to assemble said display list.

106. The method of claim 97, wherein said maintaining said display list comprises:

receiving an assemble display refresh list command indicating only one object is to be changed on the screen;

assembling pointers in said display list for only said one object.

107. The method of claim 97, wherein said executing said display list is performed during screen refresh.

108. The method of claim 107, wherein, for each of said scan lines on the display screen, said executing said display list comprises:

obtaining said pointers in said display list for a scan line of the display screen; and

obtaining said video data referenced by said pointers for said scan line of the display screen for presentation on the display screen.

109. The method of claim 97, wherein said storing said video includes storing video data having a different number of bits per pixel for different objects;

wherein said executing comprises transferring data on a data path having different data widths according to said different numbers of bits per pixel of said video data for respective objects.

110. The method of claim 109, wherein video data for a first object has a first number of bits per pixel and video data for a second object has a second number of bits per pixel;

wherein said transferring comprises dynamically reconfiguring said data path according to said first number of bits per pixel when said video data for said first object is being transferred; and

wherein said transferring comprises dynamically reconfiguring said data path according to said second number of bits per pixel when said video data for said second object is being transferred.