The debugging stub for your architecture supplies these three subroutines:
handle_exceptionto run when your program stops. You must call this subroutine explicitly in your program's startup code.
handle_exceptionto run when a trap is triggered.
handle_exception takes control when your program stops during
execution (for example, on a breakpoint), and mediates communications
with gdb on the host machine. This is where the communications
protocol is implemented;
handle_exception acts as the gdb
representative on the target machine. It begins by sending summary
information on the state of your program, then continues to execute,
retrieving and transmitting any information gdb needs, until you
execute a gdb command that makes your program resume; at that point,
handle_exception returns control to your own code on the target
handle_exception—in effect, to gdb. On some machines, simply receiving characters on the serial port may also trigger a trap; again, in that situation, you don't need to call
breakpointfrom your own program—simply running ‘target remote’ from the host gdb session gets control.
breakpoint if none of these is true, or if you simply want
to make certain your program stops at a predetermined point for the
start of your debugging session.