35-80 Vol. 3C

MODEL-SPECIFIC REGISTERS (MSRS)

35.4.1   MSRs with Model-Specific Behavior in the Silvermont Microarchitecture

Table 35-8 lists model-specific registers (MSRs) that are specific to Intel

®

 Atom™ processor E3000 Series (CPUID 

signature with DisplayFamily_DisplayModel of 06_37H) and Intel Atom processors (CPUID signatures with 
DisplayFamily_DisplayModel of 06_4AH, 06_5AH, 06_5DH). 

6

NEAR_IND_JMP

7

NEAR_REL_JMP

8

FAR_BRANCH

63:9

Reserved.

1C9H

457

MSR_LASTBRANCH_TOS

Core

Last Branch Record Stack TOS (R/W) 
Contains an index (bits 0-2) that points to the MSR containing the 

most recent branch record.
See MSR_LASTBRANCH_0_FROM_IP.

38EH

910

IA32_PERF_GLOBAL_

STATUS

Core

See Table 35-2. See Section 18.4.2, “Global Counter Control 

Facilities.” 

390H

912

IA32_PERF_GLOBAL_OVF_

CTRL

Core

See Table 35-2. See Section 18.4.2, “Global Counter Control 

Facilities.”

3F1H

1009

MSR_PEBS_ENABLE

Core

See Table 35-2. See Section 18.4.4, “Precise Event Based Sampling 

(PEBS).”

0

Enable PEBS for precise event on IA32_PMC0. (R/W)

3FAH

1018

MSR_PKG_C6_RESIDENCY

Package

Note: C-state values are processor specific C-state code names, 

unrelated to MWAIT extension C-state parameters or ACPI C-

States.

63:0

Package C6 Residency Counter. (R/O)
Value since last reset that this package is in processor-specific C6 

states. Counts at the TSC Frequency.

664H

1636

MSR_MC6_RESIDENCY_COU

NTER

Module

Module C6 Residency Counter (R/0) 
Note: C-state values are processor specific C-state code names,
unrelated to MWAIT extension C-state parameters or ACPI C-

States.

63:0

Time that this module is in module-specific C6 states since last
reset. Counts at 1 Mhz frequency.

Table 35-8.  Specific MSRs Supported by Intel® Atom™ Processors with CPUID Signature 06_37H, 06_4AH, 06_5AH, 

06_5DH

Register 

Address

Register Name

Scope

Bit Description

 Hex

Dec

606H

1542

MSR_RAPL_POWER_UNIT

Package

Unit Multipliers used in RAPL Interfaces (R/O) 
See Section 14.9.1, “RAPL Interfaces.”

Table 35-7.  MSRs Common to the Silvermont and Airmont Microarchitectures 

Register 

Address

Register Name

Scope

Bit Description

 Hex

Dec