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

Table Of Contents
Vol. 3 B-59
MODEL-SPECIFIC REGISTERS (MSRS)
79H 121 IA32_BIOS_
UPDT_TRIG
Unique BIOS Update Trigger Register. (R/W)
see Table B-2
8BH 139 IA32_BIOS_
SIGN_ID
Unique BIOS Update Signature ID. (RO)
see Table B-2
C1H 193 IA32_PMC0 Unique Performance counter register. see Table B-2
C2H 194 IA32_PMC1 Unique Performance counter register. see Table B-2
CDH 205 MSR_FSB_FREQ Shared Scaleable Bus Speed(RO).
This field indicates the intended scaleable bus
clock speed for processors based on Intel
Atom microarchitecture:
2:0 101B: 100 MHz (FSB 400)
001B: 133 MHz (FSB 533)
011B: 167 MHz (FSB 667)
133.33 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 001B.
166.67 MHz should be utilized if performing
calculation with System Bus Speed when
encoding is 011B.
63:3 Reserved
E7H 231 IA32_MPERF Unique Maximum Performance Frequency Clock
Count. (RW) see Table B-2
E8H 232 IA32_APERF Unique Actual Performance Frequency Clock Count.
(RW) see Table B-2
11EH 281 MSR_BBL_CR_
CTL3
Shared
0 L2 Hardware Enabled. (RO)
1 = If the L2 is hardware-enabled
0 = Indicates if the L2 is hardware-disabled
7:1 Reserved.
Table B-4. MSRs in Intel Atom Processor Family
Register
Address Register Name
Shared/
Unique Bit Description
Hex Dec