Sunday nothingburger for you: iPhone 18 Pro Max has a "Prepare to Ship" feature which intentionally discharges the 20 Wh battery. /usr/libexec/BatteryDischargeService handles this by calling [[NSProcessInfo processInfo] activeProcessorCount] and spawning that many NSThreads that spin until stopped
![Screenshot of Binary Ninja decompilation output:
void worker_thread_work(void* closure_data @ x20)
{
void* closure_data_1 = closure_data;
int64_t closure_data__ofs0 = data_100014f98;
if (!((uint32_t)*(uint8_t*)((char*)closure_data + closure_data__ofs0) & 1))
return;
int64_t iterations = 1;
while (true)
{
if (iterations / 1000000 * 1000000 == iterations)
{
id current_thread = [[[NSThread self] currentThread] retain];
int32_t is_cancelled = [current_thread isCancelled];
_objc_release_x19(current_thread);
if (is_cancelled & 1)
break;
}
if (!((uint32_t)*(uint8_t*)((char*)closure_data + closure_data__ofs0) & 1))
break;
bool did_overflow = iterations + 1;
iterations += 1;
if (did_overflow)
trap(1);
}
}](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:ot2275o5meirgxt2tyaziagh/bafkreientovjndwtnb4bymgxjdygdmyekrxlsv42kycx56a6emr6cvbeei)
![[TEXT TRANSCRIPTION]
Wolf: Too much of an adorably SMALL runt to be following in your father's BIG footsteps, don't you think?
Fox: Sure.
Wolf: You're too cute.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:bz42vpziagvqtu4j2sbnisum/bafkreiaj4x3wlo6lxu53adl4wmr4w3qaaybts5qksklrb2b4sjzsthby44)
