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

Table Of Contents
B-166 Vol. 3
MODEL-SPECIFIC REGISTERS (MSRS)
404H 1028 MC1_CTL
405H 1029 MC1_STATUS Bit definitions same as MC0_STATUS
406H 1030 MC1_ADDR
407H 1031 MC1_MISC Defined in MCA architecture but not implemented
in the P6 family processors
408H 1032 MC2_CTL
409H 1033 MC2_STATUS Bit definitions same as MC0_STATUS
40AH 1034 MC2_ADDR
40BH 1035 MC2_MISC Defined in MCA architecture but not implemented
in the P6 family processors
40CH 1036 MC4_CTL
40DH 1037 MC4_STATUS Bit definitions same as MC0_STATUS, except bits 0,
4, 57, and 61 are hardcoded to 1.
40EH 1038 MC4_ADDR Defined in MCA architecture but not implemented
in P6 Family processors
40FH 1039 MC4_MISC Defined in MCA architecture but not implemented
in the P6 family processors
410H 1040 MC3_CTL
411H 1041 MC3_STATUS Bit definitions same as MC0_STATUS
412H 1042 MC3_ADDR
413H 1043 MC3_MISC Defined in MCA architecture but not implemented
in the P6 family processors
NOTES
1. Bit 0 of this register has been redefined several times, and is no longer used in P6 family
processors.
2. The processor number feature may be disabled by setting bit 21 of the BBL_CR_CTL MSR
(model-specific register address 119h) to “1”. Once set, bit 21 of the BBL_CR_CTL may not be
cleared. This bit is write-once. The processor number feature will be disabled until the processor
is reset.
3. The Pentium III processor will prevent FSB frequency overclocking with a new shutdown mecha-
nism. If the FSB frequency selected is greater than the internal FSB frequency the processor will
shutdown. If the FSB selected is less than the internal FSB frequency the BIOS may choose to
use bit 11 to implement its own shutdown policy.
Table B-11. MSRs in the P6 Family Processors (Contd.)
Register
Address
Register Name Bit Description
Hex Dec