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+These are miscellaneous useful notes about how ChibiOS functions.
+
+### Stacks Configuration
+
+From ChibiOS crt0.c:
+
+Two stacks available for Cortex-M, main stack or process stack.
+
+* **Thread mode**: Used to execute application software. The processor enters Thread mode when it comes out of reset.
+* **Handler mode**: Used to handle exceptions. The processor returns to Thread mode when it has finished all exception processing.
+
+ChibiOS configures the Cortex-M in dual-stack mode. (CONTROL[1]=1)
+When CONTROL[1]=1, PSP is used when the processor is in Thread mode.
+
+MSP is always used when the processor is in Handler mode.
+
+* **__main_stack_size__**: Used for exception handlers. Yes, really.
+* **__process_stack_size__**: Used by main().
+
+After chSysInit(), the current instructions stream (usually main())
+becomes the main thread.
+
+
+##
+Original Wiki by sharebrained at [Operating System Notes](https://github.com/sharebrained/portapack-hackrf/wiki/Operating-System-Notes)
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