// Any CPU, its own clock is right under Rosetta, where RDTSC and CPUID are emulated.
// mach_absolute_time counts at the rate mach_timebase_info gives: 125/3 ns per tick on
// Apple Silicon, the 24 MHz ARM generic timer, and 1 ns per tick on x64, Rosetta included.

TIMING_SUPPORTED :: true;

timing_read_ticks :: () -> u64 #expand {
  return mach_absolute_time();
}

timing_read_tick_frequency_hz :: () -> u64 {
  info: Mach_Timebase_Info;
  if mach_timebase_info(*info) != 0 || info.numer == 0  return 0;

  // numer/denom converts ticks to nanoseconds, so ticks per second is 1e9 * denom / numer.
  return 1_000_000_000 * cast(u64) info.denom / info.numer;
}

#scope_file

Mach_Timebase_Info :: struct {
  numer: u32;
  denom: u32;
}

mach_absolute_time :: () -> u64 #foreign timing_libsystem;
mach_timebase_info :: (info: *Mach_Timebase_Info) -> s32 #foreign timing_libsystem;

timing_libsystem :: #library,system "libSystem";