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I don't understand. Are you saying that interrupts clobber the processor flags on ARM cores? That seems improbable. They'd be crashing all the time.
by lisper 4y ago
I don't understand. Are you saying that interrupts clobber the processor flags on ARM cores? That seems improbable. They'd be crashing all the time.
- zen_1 4y agoI'm guessing (since this is what my RTOS did) that interrupts were used to preempt the running task, and the OS would need to explicitly save and restore CPSR/SPSR (the arm32 processor flags) for the interrupted process, since odds are another process would be scheduled to run next, with it's own execution state and CPSR.
- Tyr42 4y agoI didn't issue the instructions to save and restore the flags register, which was the bug. It's possible to get it right.
- lisper 4y ago> I didn't issue the instructions to save and restore the flags register, which was the bug. So... you were writing your own interrupt handler then, yes?