9.10.1. A single extended handler

In some circumstances it is possible to extend the code in the exception handler to work out what the source of the exception was, and then directly call the appropriate code. In this case, you are modifying the source code for the exception handler.

Angel has been written to make this approach simple. Angel decodes SWIs and undefined instructions, and the Angel exception handlers can be extended to deal with non-Angel SWIs and undefined instructions.

However, this approach is only useful if all the sources of an exception are known when the single exception handler is written.

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