Motorola MPC823e User Manual

PowerPC Architecture Compliance
MOTOROLA MPC823e REFERENCE MANUAL 7-7
PPC ARCHITECTURE
7
COMPLIANCE
memory management unit (MMU). Instructions are not fetched from no-execute or guarded
storage and data accesses are not executed speculatively to or from the guarded storage.
The features of the MMU hardware is as follows:
• 32-entry fully associative instruction TLB
• 32-entry fully associative data TLB
• Supports up to 16 virtual address spaces
• Supports 16 access protection groups
• Supports fast software tablewalk mechanism
7.3.4 Reference and Change Bits
No reference bit is supported by the MPC823e. However, the change bit is supported by
using the data TLB error interrupt mechanism when writing to an unmodified page.
7.3.5 Storage Protection
Two main protection modes are supported by the MPC823e:
• Domain manager mode
• PowerPC mode
For more details, refer to Section 11 Memory Management Unit.
7.3.6 Storage Control Instructions
7.3.6.1 DATA CACHE BLOCK INVALIDATE (dcbi). This instruction is executed
according to the definition in
PowerPC Operating Environment Architecture (Book III) .
7.3.6.2 TLB INVALIDATE ENTRY (tlbie). This instruction is performed as defined by the
architecture, except that the 22 most-significant bits of the EA are used for address
compare.
7.3.6.3 TLB INVALIDATE ALL (tlbia). This instruction is performed as defined by the
architecture.
7.3.6.4 TLB SYNCHRONIZE (tlbsync). This instruction is implemented like a regular
mtspr instruction as it relates to engine synchronization with no further effects.
7.3.7 Interrupts
7.3.7.1 CLASSES. All interrupts associated with storage are implemented as precise
interrupts by the core, which means that a load/store instruction is not complete until all
possible error indications are sampled from the load/store bus. This also implies that a store
or nonspeculative load instruction is not issued to the load/store bus until all previous
instructions have completed. If a late error occurs, a store cycle (or a nonspeculative load
cycle) can be issued and aborted.

Motorola MPC823e Specifications

General

Brand	Motorola
Model	MPC823e
Category	Computer Hardware
Language	English