switch to f00d debug mode without bothering the debugger

f00dbg.c

// warning: the dbg exception (0x00040018) must be set to "reti"

// simply call set_dbg_mode(true) or (false) to enter or exit debug mode
// this code needs to be a separate function, do not inline it
__attribute__((noinline))
void set_dbg_mode(bool debug_mode) {
    if (!debug_mode) {
        asm(
            "ldc $0, $lp\n"
            "stc $0, $depc\n"
            "mov $0, $0\n" // per standard - no dret after stc ->depc
            "dret\n"
        );
    } else
        asm("dbreak\n");
}