Processor Configuration Registers; Register Terminology; Register Attributes And Terminology - Intel 2ND GENERATION CORE PROCESSOR FAMILY DESKTOP - DATASHEET VOLUME 2 01-2011 Datasheet

Processor Configuration Registers

2
Processor Configuration
Registers
This chapter contains the following:

• Register terminology

• PCI Devices and Functions on Processor
• System address map
• Processor register introduction
• Detailed register bit descriptions
2.1 Register Terminology
Table 2-1
in this document. Attribute modifiers are listed in
Table 2-1.

Register Attributes and Terminology

Item
RO
RW
RW1C
RW0C
RW1S
RsvdP
RsvdZ
WO
RC
RSW1C
RCW
Datasheet, Volume 2
shows the register-related terminology and register attributes that are used
Read Only: These bits can only be read by software, writes have no effect. The value of the
bits is determined by the hardware only.
Read / Write: These bits can be read and written by software.
Read / Write 1 to Clear: These bits can be read and cleared by software. Writing a '1' to a bit
will clear it, while writing a '0' to a bit has no effect. Hardware sets these bits.
Read / Write 0 to Clear: These bits can be read and cleared by software. Writing a '0' to a bit
will clear it, while writing a '1' to a bit has no effect. Hardware sets these bits.
Read / Write 1 to Set: These bits can be read and set by software. Writing a '1' to a bit will
set it, while writing a '0' to a bit has no effect. Hardware clears these bits.
Reserved and Preserved: These bits are reserved for future RW implementations and their
value must not be modified by software. When writing to these bits, software must preserve the
value read. When SW updates a register that has RsvdP fields, it must read the register value
first so that the appropriate merge between the RsvdP and updated fields will occur.
Reserved and Zero: These bits are reserved for future RW1C implementations. SW must use
0 for writes.
Write Only: These bits can only be written by software, reads return zero.
Note: Use of this attribute type is deprecated and can only be used to describe bits without
persistent state.
Read Clear: These bits can only be read by software, but a read causes the bits to be cleared.
Hardware sets these bits.
Note: Use of this attribute type is only allowed on legacy functions, as side-effects on reads are
not desirable.
Read Set / Write 1 to Clear: These bits can be read and cleared by software. Reading a bit
will set the bit to '1'. Writing a '1' to a bit will clear it, while writing a '0' to a bit has no effect.
Read Clear / Write: These bits can be read and written by software, but a read causes the
bits to be cleared.
Note: Use of this attribute type is only allowed on legacy functions, as side-effects on reads are
not desirable.
Table 2-2.
Description
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