Intel 925 - Pentium D 925 3.0GHz 800MHz 4MB-Cache Socket 775 CPU User Manual

System Address Map
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Intel
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82925X/82925XE MCH Datasheet 167
9.4 System Management Mode (SMM)
System Management Mode uses main memory for System Management RAM (SMM RAM). The
MCH supports: Compatible SMRAM (C_SMRAM), High Segment (HSEG), and Top of Memory
Segment (TSEG). System Management RAM space provides a memory area that is available for
the SMI handlers and code and data storage. This memory resource is normally hidden from the
system OS so that the processor has immediate access to this memory space upon entry to SMM.
MCH provides three SMRAM options:
• Below 1-MB option that supports compatible SMI handlers.
• Above 1-MB option that allows new SMI handlers to execute with write-back cacheable
SMRAM.
• Optional TSEG area of 1 MB, 2 MB, or 8 MB in size.
The above 1-MB solutions require changes to compatible SMRAM handler’s code to properly
execute above 1 MB.
Note: DMI and PCI Express masters are not allowed to access the SMM space.
9.4.1 SMM Space Definition
SMM space is defined by its addressed SMM space and its DRAM SMM space. The addressed
SMM space is defined as the range of bus addresses used by the processor to access SMM space.
DRAM SMM space is defined as the range of physical main memory locations containing the
SMM code. SMM space can be accessed at one of three transaction address ranges: Compatible,
High, and TSEG. The Compatible and TSEG SMM space is not remapped; therefore, the
addressed and DRAM SMM space is the same address range. Since the High SMM space is
remapped, the addressed and DRAM SMM space are different address ranges. Note that the High
DRAM space is the same as the Compatible Transaction Address space. The following table
describes three unique address ranges:
• Compatible Transaction Address
• High Transaction Address
• TSEG Transaction Address
SMM Space Enabled Transaction Address Space DRAM Space (DRAM)
Compatible (C) 000A_0000h to 000B_FFFFh 000A_0000h to 000B_FFFFh
High (H) FEDA_0000h to FEDB_FFFFh 000A_0000h to 000B_FFFFh
TSEG (T) (TOLUD-STOLEN-TSEG) to
TOLUD-STOLEN
(TOLUD-STOLEN-TSEG) to
TOLUD-STOLEN

Intel 925 - Pentium D 925 3.0GHz 800MHz 4MB-Cache Socket 775 CPU Specifications

General

Brand	Intel
Model	925 - Pentium D 925 3.0GHz 800MHz 4MB-Cache Socket 775 CPU
Category	Computer Hardware
Language	English