Exception Table Relocation (Etr); Etr Overview - Motorola MPC533 Reference Manual

Exception Table Relocation (ETR)

4.3 Exception Table Relocation (ETR)
4.3.1

ETR Overview

The BBC is able to relocate the exception addresses of the RCPU. The relocation feature
always maps the exception addresses into the internal memory space of the MPC533. See
Figure 4-2. This feature is important in multi-MPC533 systems, where, although the
memory map in some was shifted to not be on the lower 4 Mbytes, their RCPU cores can
still access their exception handlers in their internal flash in spite of several RCPUs issuing
the same exception addresses.
The relocation also saves wasted space between the exception table entries in the case
where each exception entry contained only a branch instruction to the exception routine,
which is located elsewhere.
The exception vector table may be programmed to be located in four places in the MPC533
internal memory space.
The exception table relocation is supported in both decompression on and decompression
off operation modes.
The RESET routine vector is relocated differently in decompression on and in
decompression off modes. This feature may be used by a software code compression tool
to guarantee that a vocabulary table initialization routine is always executed before
application code is running.
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