Interrupts using the ARM core and the GIC

These are interrupt handler stubs. They do nothing as you can see - except when an interrupt is caught it gets into the infinite while(1).

If you pause the execution of the program via JTAG, and suppose you had an unhandled interrupt - it will be caught in the stub so that you can see it.

If these interrupts were not installed, at least in the gcc toolchain version you have these stubs defined as 'weak' in a library - meaning that they would be used only if the user did not supply any other function. They still do an infinite loop though, but this time in assembly and it's a bit more difficult to understand where you crashed.

So, for your question, these prototype function definitions are there for programming / debugging convenience.

The reset handler should really not be written like this but rather perform basic runtime initialization of the processor and pass control to main(). you need to remove the __cs3_reset implementation above and try to compile again. If your project was setup correctly you should have a reset vector implementation prepared for you in assembly.

Good luck with your embedded design

Guy Shemesh

ePiccolo Engineering