Intel D15343-003 - Manual (Page 134)

Intel
®
82854 Graphics Memory Controller Hub (GMCH)
134 D15343-003
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.
6.4.4.2 Alpha 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.
6.4.5 Planes 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.
6.4.5.1 Dual 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.
6.4.6 Hardware 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.
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