VT8601 Via, VT8601 Datasheet - Page 132

• Manufacturer Part Number: VT8601
• Description: Slot-1 / Socket-370 PCI North Bridge
• Manufacturer: Via

Pixel Engine Registers
The major responsibilities of the Pixel Engine are to perform
per-pixel operations and to control data flow and its sequence.
The Pixel engine interfaces to the Rasterization Engine and
the host to accept data. It also interfaces to the Memory
Interface to access video memory. Inside the Pixel Engine,
there are several blocks: the Span Engine, the Data Path, and
the Texture Engine.
Texture Engine are under control of the Span Engine. The
Memory Interface accepts memory access requests from the
Pixel Engine, translates the address into a linear address, and
executes the requests.
The 0 - FFh “Engine” register address space is partitioned
into six sections:
Addresses 40h - FFh are also used for sequential loading
overlapping with other registers in this space.
10000
Revision 1.3 September 8, 1999
A0 – AFh
B0 – BFh
C0 – FFh
10 - 2Fh
30 - 3Fh
44 - 9Fh
0 - 0Fh
Span
7HFKQRORJLHV ,QF
A
-
:H &
:H &R R QQHFW
AGP
1FFFFh
QQHFW
Span Engine
VGA core
Unified Rasterization and Setup Engines
Pixel Engine
Texture Engine
Command List Control Unit
Memory Interface
Memory Interface
Data Path
are
Operation of the Data Path and the
D
used
Rasterization
as
a
Texture Engine
data
A
port
Addresses
D
area.
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Data from the Host
The Pixel Engine can accept data from the host through either
the 32-bit data port register at 9Ch or data in the 1xxxh
address space. Software passes only enough DWORDs to
hardware.
boundaries. It only packs to 32-bit boundaries. For bitblts,
packing is done per-scanline. I.e., for every scanline, the host
will send just enough DWORDs to the engine.
packing is done per-command.
broken inside a DWORD. For a string of texts, the number of
DWORDs of data passed to the Graphic Engine can be odd
numbers except for the last character. For the last character,
software should pass either an even number of DWORDs (by
padding a garbage DWORD as necessary) or by setting a
drawing environment register after all data is sent.
Software doesn’t pack data to 64-bit
VT8601 Apollo ProMedia
3D Graphics Engine Registers
I.e., the scanline may be
For text,