Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
Vol. 3 B-107
MODEL-SPECIFIC REGISTERS (MSRS)
Setting this can cause unexpected
behavior to software that
depends on the availability of
CPUID leaves greater than 3.
23 Shared xTPR Message Disable. (R/W)
see Table B-2.
24 L1 Data Cache Context Mode.
(R/W)
When set, the L1 data cache is
placed in shared mode; when clear
(default), the cache is placed in
adaptive mode. This bit is only
enabled for IA-32 processors that
support Intel Hyper-Threading
Technology. See Section 10.5.6,
“L1 Data Cache Context Mode.”
When L1 is running in adaptive
mode and CR3s are identical, data
in L1 is shared across logical
processors. Otherwise, L1 is not
shared and cache use is
competitive.
If the Context ID feature flag
(ECX[10]) is set to 0 after
executing CPUID with EAX = 1, the
ability to switch modes is not
supported. BIOS must not alter the
contents of
IA32_MISC_ENABLE[24].
33:25 Reserved.
34 Unique XD Bit Disable. (R/W)
see Table B-2.
63:35 Reserved.
1A1H 417 MSR_PLATFORM_BRV 3, 4, 6 Shared Platform Feature Requirements.
(R)
17:0 Reserved.
Table B-6. MSRs in the Pentium 4 and Intel Xeon Processors (Contd.)
Register
Address
Register Name
Fields and Flags
Model
Avail-
ability
Shared/
Unique
1
Bit Description
Hex Dec