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

Table Of Contents
Vol. 3 B-151
MODEL-SPECIFIC REGISTERS (MSRS)
3 Automatic Thermal Control Circuit Enable. (R/W)
1 = Setting this bit enables the thermal control
circuit (TCC) portion of the Intel Thermal
Monitor feature. This allows processor clocks
to be automatically modulated based on the
processor's thermal sensor operation.
0 = Disabled (default).
The automatic thermal control circuit enable bit
determines if the thermal control circuit (TCC) will
be activated when the processor's internal
thermal sensor determines the processor is about
to exceed its maximum operating temperature.
When the TCC is activated and TM1 is enabled, the
processors clocks will be forced to a 50% duty
cycle. BIOS must enable this feature.
The bit should not be confused with the on-
demand thermal control circuit enable bit.
6:4 Reserved.
7 Performance Monitoring Available. (R)
1 = Performance monitoring enabled
0 = Performance monitoring disabled
9:8 Reserved.
10 FERR# Multiplexing Enable. (R/W)
1 = FERR# asserted by the processor to indicate
a pending break event within the processor
0 = Indicates compatible FERR# signaling
behavior
This bit must be set to 1 to support XAPIC
interrupt model usage.
Branch Trace Storage Unavailable. (RO)
1 = Processor doesn’t support branch trace
storage (BTS)
0 = BTS is supported
Table B-10. MSRs in Pentium M Processors (Contd.)
Register
Address
Register Name Bit Description
Hex Dec