Intel G870 BX80623G870 User Manual

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Datasheet, Volume 1

The WIZ unit performs an early depth test, which removes failing pixels and eliminates 
unnecessary processing overhead. 

The Windower uses the parameters provided by the SF unit in the object-specific 
rasterization algorithms. The WIZ unit rasterizes objects into the corresponding set of 
pixels. The Windower is also capable of performing dithering, whereby the illusion of a 
higher resolution when using low-bpp channels in color buffers is possible. Color 
dithering diffuses the sharp color bands seen on smooth-shaded objects.

The Video Engine handles the non-3D (media/video) applications. It includes support 
for VLD and MPEG2 decode in hardware. 

The 2D Engine contains BLT (Block Level Transfer) functionality and an extensive set of 
2D instructions. To take advantage of the 3D during engine’s functionality, some BLT 
functions make use of the 3D renderer.

The 2D registers consists of original VGA registers and others to support graphics 
modes that have color depths, resolutions, and hardware acceleration features that go 
beyond the original VGA standard.

This BLT engine accelerates the GUI of Microsoft Windows* operating systems. The 
128-bit BLT engine provides hardware acceleration of block transfers of pixel data for 
many common Windows operations. The BLT engine can be used for the following:

• Move rectangular blocks of data between memory locations
• Data alignment 
• To perform logical operations (raster ops)

The rectangular block of data does not change, as it is transferred between memory 
locations. The allowable memory transfers are between: cacheable system memory 
and frame buffer memory, frame buffer memory and frame buffer memory, and within 
system memory. Data to be transferred can consist of regions of memory, patterns, or 
solid color fills. A pattern is always 8 x 8 pixels wide and may be 8, 16, or 32 bits per 
pixel.

The BLT engine expands monochrome data into a color depth of 8, 16, or 32 bits. BLTs 
can be either opaque or transparent. Opaque transfers move the data specified to the 
destination. Transparent transfers compare destination color to source color and write 
according to the mode of transparency selected.

Data is horizontally and vertically aligned at the destination. If the destination for the 
BLT overlaps with the source memory location, the BLT engine specifies which area in 
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 BLT engine has instructions to invoke BLT and stretch BLT operations, permitting 
software to set up instruction buffers and use batch processing. The BLT engine can 
perform hardware clipping during BLTs.