e200z335 Core Complex Overview
e200z3 Power Architecture Core Reference Manual, Rev. 2
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Freescale Semiconductor
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Processors built on the Power ISA can use IVPR and the IVORs to set exception vectors
individually, but they can be set to the address offsets defined in the OEA to provide compatibility.
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Unlike the original version of the PowerPC architecture, the Power ISA does not define a reset
vector; execution begins at a fixed virtual address, 0xFFFF_FFFC. The e200z3 allows this to be
hard-wired to any page.
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Some Power ISA and e200z3 core-specific SPRs are different from those defined in the original
PowerPC architecture, particularly those related to MMU functions. Much of this information has
been moved to the new exception syndrome register (ESR).
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Timer services are generally compatible. However, the Power ISA defines a decrementer
auto-reload feature, and two critical-type interrupts—the fixed-interval timer and the watchdog
timer interrupts—all of which are implemented in the e200z3 core.
An overview of the interrupt and exception handling capabilities of the e200z3 core can be found in
Section 1.5, “Interrupts and Exception Handling.”
1.7.4
Memory Management
The e200z3 core implements a straightforward virtual address space that complies with the Power ISA
MMU definition, which eliminates segment registers and block address translation resources. The Power
ISA defines resources for multiple, variable page sizes that can be configured in a single implementation.
TLB management is provided with new instructions and SPRs.
1.7.5
Reset
Cores built on the Power ISA do not share a common reset vector with the original PowerPC architecture.
Instead, at reset, fetching begins at address 0xFFFF_FFFC. In addition to the Power ISA reset definition,
the EIS and the e200z3 core define specific aspects of the MMU page translation and protection
mechanisms. Unlike the original PowerPC core, as soon as instruction fetching begins, the e200z3 core is
in virtual mode with a hardware-initialized TLB entry.
1.7.6
Little-Endian Mode
Unlike the original PowerPC architecture, where little-endian mode is controlled on a system basis, the
Power ISA allows control of byte ordering on a memory-page basis. Additionally, the little-endian mode
used in the Power ISA is true little-endian byte ordering (byte invariance).
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