Specification Sheet

Datasheet, Volume 2 of 2 27
Processor Configuration Register Definitions and Address Ranges
2 Processor Configuration
Register Definitions and
Address Ranges
This chapter describes the processor configuration register, I/O, and memory address
ranges. The chapter provides register terminology. PCI Devices and Functions are
described.
Note: Processor Graphics does not apply to X-Series processor.
2.1 Register Terminology
Register Attributes and Terminology table lists the register-related terminology and
access attributes that are used in this document. Register Attribute Modifiers table
provides the attribute modifiers.
Table 2-1. Register Attributes and Terminology
Item Description
RO
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.
RW Read / Write: These bits can be read and written by software.
RW1C
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.
RW0C
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.
RW1S
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.
RsvdP
Reserved and Preserved: These bits are reserved for future RW implementations and their
value should not be modified by software. When writing to these bits, software should preserve
the value read. When SW updates a register that has RsvdP fields, it should read the register
value first so that the appropriate merge between the RsvdP and updated fields will occur.
RsvdZ
Reserved and Zero: These bits are reserved for future RW1C implementations. Software should
use 0 for writes.
WO
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.
RC
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
RSW1C
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.
RCW
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.