Intel D15343-003 manual Planes and Engines, Hardware Cursor Plane Native Graphic Mode only

Intel® 82854 Graphics Memory Controller Hub (GMCH)

Data is horizontally and vertically aligned at the destination. If the destination for the BLT overlaps with the source system memory location, the GMCH can specify which area in system memory to begin the BLT transfer. Hardware is included for all 256 raster operations (source, pattern, and destination) defined by Microsoft, including transparent BLT.

The GMCH has instructions to invoke BLT operations, permitting software to set up instruction buffers and use batch processing as described in the Instruction Processing section. The GMCH can perform hardware clipping during BLTs.

6.4.4.2Alpha Stretch BLT

The stretch BLT function can stretch source data in the X and Y directions to a destination larger or smaller than the source. Stretch BLT functionality expands a region of system memory into a larger or smaller region using replication and interpolation. The stretch BLT function also provides format conversion and data alignment.

6.4.5Planes and Engines

The GMCH display can be functionally delineated into planes and engines (pipes and ports). A plane consists of rectangular shaped image that has characteristics such as source, size, position, method, and format. These planes get attached to source surfaces, which are rectangular system memory surfaces with a similar set of characteristics. They are also associated with a particular destination pipe.

A pipe consists of a set of planes that will be combined with a timing generator. A port is the destination for the result of the pipe. The GMCH supports one Analog Output Port and two DVO ports. In conclusion, planes are associated with pipes and pipes are associated with ports.

6.4.5.1Dual Pipe Independent Display Functionality (Native Graphic Mode only)

The display consists of two display pipes, A and B. Pipes have a set of planes that are assigned to them as sources. The analog display port may only use Pipe A or Pipe B, the DVO B or C ports may use either Pipe A or Pipe B. This limits the resolutions available on a digital display when an analog CRT is active.

Table 31. Dual Display Usage Model (Native Graphic Mode only)

Display Pipe A	Display Pipe B
DVO B or C or Both	CRT
CRT	DVO B or C or Both
DVO B	DVO C

6.4.6Hardware Cursor Plane (Native Graphic Mode only)

The GMCH supports two hardware cursors. The cursor plane is one of the simplest display planes. With a few exceptions, has a fixed size of 64 x 64 and a fixed Z-order (top). In legacy modes, cursor can cause the display data below it to be inverted. In the alpha blend mode, true color cursor data can be alpha blended into the display stream. It can be assigned to either display pipe A or display pipe B and dynamically flipped from one to the other when both are running.

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