82801DB Datasheet, PDF (485/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

AC ’97 Audio Controller Registers (D31:F5)
14.2.5
x_PICB—Position In Current Buffer Register
I/O Address:
Default Value:
Lockable:
NABMBAR + 08h (PIPICB),
NABMBAR + 18h (POPICB),
NABMBAR + 28h (MCPICB)
MBBAR + 48h (MC2PICB)
MBBAR + 58h (PI2PICB)
MBBAR + 68h (SPPICB)
0000h
No
Attribute:
Size:
Power Well:
RO
16 bits
Core
Software can read the registers at the offsets 08h, 0Ah, and 0Bh by performing a 32-bit read from
the address offset 08h. Software can also read this register individually by doing a single, 16-bit
read to offset 08h. Reads across DWord boundaries are not supported.
Bit
Description
Position In Current Buffer [15:0] — RO. These bits represent the number of samples left to be
processed in the current buffer. Once again, this means, the number of samples not yet read from
15:0 memory (in the case of reads from memory) or not yet written to memory (in the case of writes to
memory), irrespective of the number of samples that have been transmitted/received across AC-
link.
14.2.6
x_PIV—Prefetched Index Value Register
I/O Address:
Default Value:
Lockable:
NABMBAR + 0Ah (PIPIV),
NABMBAR + 1Ah (POPIV),
NABMBAR + 2Ah (MCPIV)
MBBAR + 4Ah (MC2PIV)
MBBAR + 5Ah (PI2PIV)
MBBAR + 6Ah (SPPIV)
00h
No
Attribute:
Size:
Power Well:
RO
8 bits
Core
Software can read the registers at the offsets 08h, 0Ah, and 0Bh by performing a 32-bit read from
the address offset 08h. Software can also read this register individually by doing a single, 8-bit read
to offset 0Ah. Reads across DWord boundaries are not supported.
Bit
Description
7:5 Hardwired to 0.
4:0
Prefetched Index Value [4:0] — RO. This field indicates which buffer descriptor in the list has been
prefetched. The bits in this register are also modulo 32 and roll over after they reach 31.
Intel^® 82801DB ICH4 Datasheet
485