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 an SVC 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 SVCs.
In such situations the following approaches can be taken to
extend the exception handling code:
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