Integrated Functions (Continued)
Table 4-9. Internal Bus Interface Unit Registers
Bit
Name
Description
14
SMIC
SMIC: All I/O accesses for address range 3C0h to 3CFh generate an SMI: 0 = Disable; 1 = Enable.
(Used for VGA virtualization.)
13
SMIB
SMIB: All I/O accesses for address range 3B0h to 3BFh generate an SMI: 0 = Disable; 1 = Enable
(Used for VGA virtualization.)
12:8
7
RSVD
XPD
Reserved: Set to 0.
X-Bus Pipeline: The address for the next cycle can be driven on the X-Bus before the completion of the
data phase of the current cycle.
0 = Enable
1 = Disable
6
5
4
GNWS
XNWS
GEA
X-Bus Graphics Pipe No Wait State: Data driven on the X-Bus from the graphics pipeline:
0 = 1 full clock before X_DSX is asserted
1 = On the same clock in which X_RDY is asserted
X-Bus No Wait State: Data driven on the X-Bus from the internal bus interface unit:
0 = 1 full clock before X_DSX is asserted
1 = On the same clock in which X_RDY is asserted
Graphics Enable for A Region: Allow memory R/W operations for address range B8000h to BFFFFh
be directed to the graphics pipeline: 0 = Disable; 1 = Enable. If enabled, the GEA region is always non-
cacheable. In the region control field (A0) the cache enable bit (bit2) is ignored.
(Used for VGA emulation.)
3:0
A0
A0 Region: Region control field for address range A0000h to AFFFFh.
Note: Refer to Table 4-10 on page 106 for decode.
GX_BASE+8008h-800Bh
BC_XMAP_2 Register (R/W)
Default Value = 00000000h
31:28
27:24
23:20
19:16
15:12
11:8
DC
D8
D4
D0
CC
C8
C4
C0
DC Region: Region control field for address range DC000h to DFFFFh.
D8 Region: Region control field for address range D8000h to DBFFFh.
D4 Region: Region control field for address range D4000h to D7FFFh.
D0 Region: Region control field for address range D0000h to D3FFFh.
CC Region: Region control field for address range CC000h to CFFFFh.
C8 Region: Region control field for address range C8000h to CBFFF.
C4 Region: Region control field for address range C4000h to C7FFFh.
C0 Region: Region control field for address range C0000h to C3FFFh.
7:4
3:0
Note: Refer to Table 4-10 on page 106 for decode.
GX_BASE+800Ch-800Fh
BC_XMAP_3 Register (R/W)
Default Value = 00000000h
31:28
27:24
23:20
19:16
15:12
11:8
FC
F8
F4
F0
EC
E8
E4
E0
FC Region: Region control field for address range FC000h to FFFFFh.
F8 Region: Region control field for address range F8000h to FBFFFh.
F4 Region: Region control field for address range F4000h to F7FFFh.
F0 Region: Region control field for address range F0000h to F3FFFh.
EC Region: Region control field for address range EC000h to EFFFFh.
E8 Region: Region control field for address range E8000h to EBFFFh.
E4 Region: Region control field for address range E4000h to E7FFFh.
E0 Region: Region control field for address range E0000h to E3FFFh.
7:4
3:0
Note: Refer to Table 4-10 on page 106 for decode.
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