delay.h

/*
  Copyright (c) 2014 Arduino.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/**
 * @file delay.h
 * @brief Delay implementation
 */

#include "types.h"
#include "stm32.h"

#ifndef _DELAY_H_
#define _DELAY_H_

/**
 * @brief Delay the given number of microseconds.
 *
 * @param us Number of microseconds to delay.
 */
static inline void delay_us(uint32 us) {
    us *= STM32_DELAY_US_MULT;

    /* fudge for function call overhead  */
    //us--;
    asm volatile("   mov r0, %[us]          \n\t"
                 "1: subs r0, #1            \n\t"
                 "   bhi 1b                 \n\t"
                 :
                 : [us] "r" (us)
                 : "r0");
}

static inline void delay_ns100(uint32 us) {
    us *= STM32_DELAY_US_MULT;
	us /= 10;

    /* fudge for function call overhead  */
    //us--;
    asm volatile("   mov r0, %[us]          \n\t"
                 "1: subs r0, #1            \n\t"
                 "   bhi 1b                 \n\t"
                 :
                 : [us] "r" (us)
                 : "r0");
}
#endif