6.12. Chaining exception handlers
In some situations there can be several different sources
of a particular exception. For example:
Angel
uses an Undefined Instruction to implement breakpoints. However, Undefined
Instruction exceptions also occur when a coprocessor instruction
is executed, and no coprocessor is present.
Angel uses a SWI for various purposes, such as entering
Supervisor mode from User mode and supporting semihosting requests
during development. However, a Real Time Operating System (RTOS) or
an application might also implement some SWIs.
In such situations the following approaches can be taken to
extend the exception handling code:
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