-#if defined(__ppc__) || defined(__ppc64__)
-
-/* This syscall is special cased: the timeval is returned in r3/r4.
- * Note also that the "seconds" field of the timeval is a long, so
- * it's size is mode dependent.
+/*
+ * A third argument, of type uint64_t*, was added to the gettimeofday syscall
+ * for use cases that also want to know the mach_absolute_time that matches the
+ * time value returned.
+ *
+ * __gettimeofday takes the traditional two arguments. It will zero out the
+ * third argument argument before entering the kernel, behaving like the old
+ * call.
+ *
+ * __gettimeofday_with_mach will pass it through and supporting kernels will
+ * copy-out the mach_absolute_time. Old kernels will leave the pointed to
+ * value alone.