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dev:crosscompiler:backend_arm:code_generator [2021/07/27 08:25] – [Exception Stackframe] ursgraf | dev:crosscompiler:backend_arm:code_generator [2021/07/27 08:27] – [Exception Stackframe] ursgraf | ||
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===== Exception Stackframe ===== | ===== Exception Stackframe ===== | ||
- | In case of an exception all volatile GPRs together with LR must be saved. The Further, the nonvolatile GPRs which are used in this method must be saved as well. \\ | + | In case of an exception all volatile GPRs together with LR must be saved. The scratch register R6 must be saved first, because it is used to save the original stack pointer before any other registers can be pushed. The nonvolatile GPRs which are used in this method must be saved as well. \\ |
EXTR's need no saving, as they are not allowed to be used in exceptions. If an exception method calls a method where EXTR are used (e.g. in an interrupt handler or in a timer subclass) you have to use '' | EXTR's need no saving, as they are not allowed to be used in exceptions. If an exception method calls a method where EXTR are used (e.g. in an interrupt handler or in a timer subclass) you have to use '' | ||