// Loop through all the triggers that *could* be set, and start/end alarms
            // depending on those that are/were/aren't/weren't. N.B. op::clz is defined
            // in intrin.h, and serves as a portable wrapper to GCC's count-leading-zeroes
            // intrinsic (https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html)
            const int lastSource = (sourceMask[subsystem] ? 0 : op::clz(sourceMask[subsystem]));
            for (alarm_source_id_t source_id = 0; source_id < lastSource; source_id++) {

                if (!(sourceMask[subsystem] & (uint64_t(1) << source_id))) {
                    // If this source wasn't masked into this particular interrogation,
                    // we can't say anything about alarms that may or may not be active
                    // under it. In order to avoid falsely claiming that such alarms have
                    // ended, we need to skip all the below logic in such a case.
                    continue;
                }

                // ........
            }