20 www.xilinx.com PowerPC™ 405 Processor Block Reference Guide
1-800-255-7778 UG018 (v2.0) August 20, 2004
Chapter 1: Introduction to the PowerPC 405 Processor
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Table 1-2: OEA Features of the PowerPC Embedded-Environment Architecture
Operating
Environment Features
Register model xPrivileged special-purpose registers (SPRs) and instructions for accessing those
registers
xDevice control registers (DCRs) and instructions for accessing those registers
Storage model xPrivileged cache-management instructions
xStorage-attribute controls
xAddress translation and memory protection
xPrivileged TLB-management instructions
Exception model xDual-level interrupt structure supporting various exception types
xSpecification of interrupt priorities and masking
xPrivileged SPRs for controlling and handling exceptions
xInterrupt-control instructions
xSpecification of how partially executed instructions are handled when an interrupt
occurs
Debug model xPrivileged SPRs for controlling debu g modes and debug events
xSpecification for seven types of debug events
xSpecification for allowing a debug event to cause a reset
xThe ability of the debug mechanism to freeze the timer resources
Time-keeping model x64-bit time base
x32-bit decrementer (the programmable-interval timer)
xThree timer-event interrupts:
iProgrammable-interval timer (PIT)
iFixed-interval timer (FIT)
iWatchdog timer (WDT)
xPrivileged SPRs for controlling the timer resources
xThe ability to freeze the timer resources using the debug mechanism
Synchronization
requirements
xRequirements for special registers and the TLB
xRequirements for instruction fetch and for data access
xSpecifications for context synchronization and executio n synchronization
Reset and initialization
requirements
xSpecification for two internal mechanisms that can cause a reset:
iDebug-control register (DBCR)
iTimer-control register (T CR)
xContents of processor resources after a reset
xThe software-initialization requirements, including an initialization code example