Function __clock_cycles

src/platforms/esp/8266/clockless_esp8266.h:22–26

Info on reading cycle counter from https://github.com/kbeckmann/nodemcu-firmware/blob/ws2812-dual/app/modules/ws2812.c

// Info on reading cycle counter from https://github.com/kbeckmann/nodemcu-firmware/blob/ws2812-dual/app/modules/ws2812.c
__attribute__ ((always_inline)) inline static u32 __clock_cycles() {
  u32 cyc;
  __asm__ __volatile__ ("rsr %0,ccount":"=a" (cyc)) FL_NOEXCEPT;
  return cyc;
}

#define FL_CLOCKLESS_CONTROLLER_DEFINED 1