#include "sys_delay.h"

/*120Mhz时钟时，当ulCount为1时，函数耗时3个时钟，延时=3*1/120us=1/40us*/
/*
SystemCoreClock=120000000

us级延时,延时n微秒
SysCtlDelay(n*(SystemCoreClock/3000000));

ms级延时,延时n毫秒
SysCtlDelay(n*(SystemCoreClock/3000));

m级延时,延时n秒
SysCtlDelay(n*(SystemCoreClock/3));
*/

#if defined   (__CC_ARM) /*!< ARM Compiler */
__asm void
SysCtlDelay(unsigned long ulCount)
{
    subs    r0, #1;
    bne     SysCtlDelay;
    bx      lr;
}
#elif defined ( __ICCARM__ ) /*!< IAR Compiler */
void
SysCtlDelay(unsigned long ulCount)
{
    __asm("    subs    r0, #1\n"
       "    bne.n   SysCtlDelay\n"
       "    bx      lr");
}
#elif defined (__GNUC__) /*!< GNU Compiler */
void __attribute__((naked))
SysCtlDelay(unsigned long ulCount)
{
    __asm("    subs    r0, #1\n"
       "    bne     SysCtlDelay\n"
       "    bx      lr");
}

#elif defined  (__TASKING__) /*!< TASKING Compiler */                           
/*无*/
#endif /* __CC_ARM */


void Sys_delay_ms(unsigned long ulCount)
{
   SysCtlDelay(ulCount*(SystemCoreClock/3000));
}


/**
  * @}
  */


/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/