Delay utilite for STM8 family

get form https://github.com/Hoksmur/stm8_routines/blob/master/delay.h

/* 
 * delay utilite for STM8 family
 * COSMIC and SDCC
 * Terentiev Oleg
 * t.oleg@ymail.com
 */

#ifndef _UTIL_DELAY_H_
#define _UTIL_DELAY_H_ 1

#define F_CPU 2000000UL

#ifndef F_CPU
#warning F_CPU is not defined!
#endif

/* 
 * Func delayed N cycles, where N = 3 + ( ticks * 3 )
 * so, ticks = ( N - 3 ) / 3, minimum delay is 6 CLK
 * when tick = 1, because 0 equels 65535
 */

static inline void _delay_cycl( unsigned short __ticks )
{
#if defined(__CSMC__)
/* COSMIC */
  #define T_COUNT(x) (( F_CPU * x / 1000000UL )-3)/3)
    // ldw X, __ticks ; insert automaticaly
    _asm("nop\n $N:\n decw X\n jrne $L\n nop\n ", __ticks);
#elif defined(__SDCC)
  #define T_COUNT(x) (( F_CPU * x / 1000000UL )-5)/5)
    __asm__("nop\n nop\n"); 
    do {         // ASM: ldw X, #tick; lab$: decw X; tnzw X; jrne lab$
                __ticks--;//      2c;                 1c;     2c    ; 1/2c   
        } while ( __ticks );
    __asm__("nop\n");
#elif defined(__RCST7__)
/* RAISONANCE */
  #error ToDo for RAISONANCE
#elif defined(__ICCSTM8__)
/* IAR */
  #error ToDo for IAR
#else
 #error Unsupported Compiler!          /* Compiler defines not found */
#endif
}

static inline void _delay_us( const unsigned short __us )
{
    _delay_cycl( (unsigned short)( T_COUNT(__us) );
}

static inline void _delay_ms( unsigned short __ms )
{
    while ( __ms-- )
    {
        _delay_us( 1000 );
    }
}

#endif