VT8601 Via, VT8601 Datasheet - Page 134

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

GEbase + 48 – Raster Operation (ROP) ......................... RW
Revision 1.3 September 8, 1999
31-8 Reserved
7-0
7HFKQRORJLHV ,QF
ROP3 Code
:H &
:H &R R QQHFW
QQHFW
........................................ always reads 0
-128
GEbase + 4C – Z Function ............................................... RW
30-17 Reserved
16-7 Z-Bias Value
4-3
2-0
31
6
5
Z-Bias
Test Alpha
Z-Buffer Write
Reserved
Z-Buffer Compare
000 Compare False. Z and RGB values will not be
001 Compare Less Than. Z and RGB values will
010 Compare Equal. Z and RGB values will be
011 Compare Less Than or Equal. Z and RGB
100 Compare Greater Than. Z and RGB values
101 Compare Not Equal. Z and RGB values will
110 Compare Greater Than or Equal. Z and RGB
111 Compare True. Z and RGB values will be
0
1
0
1
0
1
Disable
Enable
Disable
Enable
Disable
Enable
written to memory.
be written to memory if the current Z value is
less than the Z value in memory.
written to memory if the current Z value is
equal to the Z value in memory.
values will be written to memory if the current
Z value is less than the Z value in memory.
will be written to memory if the current Z
value is greater than the Z value in memory.
be written to memory if the current Z value is
not equal to the Z value in memory.
values will be written to memory if the current
Z value is greater than or equal to the Z value
in memory.
written to memory.
........................................ always reads 0
........................................always reads 0
VT8601 Apollo ProMedia
3D Graphics Engine Registers