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3-176 Vol. 2A CPUID—CPU Identification
INSTRUCTION SET REFERENCE, A-M
13 PGE PTE Global Bit. The global bit in page directory entries (PDEs) and page table
entries (PTEs) is supported, indicating TLB entries that are common to
different processes and need not be flushed. The CR4.PGE bit controls this
feature.
14 MCA Machine Check Architecture. The Machine Check Architecture, which
provides a compatible mechanism for error reporting in P6 family, Pentium 4,
Intel Xeon processors, and future processors, is supported. The MCG_CAP
MSR contains feature bits describing how many banks of error reporting
MSRs are supported.
15 CMOV Conditional Move Instructions. The conditional move instruction CMOV is
supported. In addition, if x87 FPU is present as indicated by the CPUID.FPU
feature bit, then the FCOMI and FCMOV instructions are supported
16 PAT Page Attribute Table. Page Attribute Table is supported. This feature
augments the Memory Type Range Registers (MTRRs), allowing an operating
system to specify attributes of memory on a 4K granularity through a linear
address.
17 PSE-36 36-Bit Page Size Extension. Extended 4-MByte pages that are capable of
addressing physical memory beyond 4 GBytes are supported. This feature
indicates that the upper four bits of the physical address of the 4-MByte
page is encoded by bits 13-16 of the page directory entry.
18 PSN Processor Serial Number. The processor supports the 96-bit processor
identification number feature and the feature is enabled.
19 CLFSH CLFLUSH Instruction. CLFLUSH Instruction is supported.
20 Reserved Reserved
21 DS Debug Store. The processor supports the ability to write debug information
into a memory resident buffer. This feature is used by the branch trace store
(BTS) and precise event-based sampling (PEBS) facilities (see Chapter 18,
“Debugging and Performance Monitoring,” in the Intel® 64 and IA-32
Architectures Software Developer’s Manual, Volume 3B).
22 ACPI Thermal Monitor and Software Controlled Clock Facilities. The processor
implements internal MSRs that allow processor temperature to be monitored
and processor performance to be modulated in predefined duty cycles under
software control.
23 MMX Intel MMX Technology. The processor supports the Intel MMX technology.
24 FXSR FXSAVE and FXRSTOR Instructions. The FXSAVE and FXRSTOR instructions
are supported for fast save and restore of the floating point context.
Presence of this bit also indicates that CR4.OSFXSR is available for an
operating system to indicate that it supports the FXSAVE and FXRSTOR
instructions.
Table 3-16. More on Feature Information Returned in the EDX Register (Contd.)
Bit # Mnemonic Description