#include <dwt_delay.h>

extern uint32_t SystemCoreClock;


//定义需使能位
#define    DEM_CR_TRCENA    (1u<<24)
#define    DWT_CR_CYCCNTENA (1u<<0)


//DWT init
void DWT_Init(void)
{
    DEM_CR |= (uint32_t)DEM_CR_TRCENA;
    DWT_CYCCNT = (uint32_t)0u;
    DWT_CR |= (uint32_t)DWT_CR_CYCCNTENA;
}

void DWT_DelayUs(uint32_t us)
{
    uint32_t start = DWT_CYCCNT;
    uint32_t cycles = us * (SystemCoreClock / 1000000);
    uint32_t elapsed;

    while (1) {
        uint32_t current = DWT_CYCCNT;
        if (current >= start) {
            elapsed = current - start;
        } else {
            elapsed = (0xFFFFFFFFu - start) + current; // 处理溢出
        }
        if (elapsed >= cycles) break;
    }
}

void DWT_DelayMs(uint32_t ms)
{
    for (uint32_t i = 0; i < ms; i++) {
        DWT_DelayUs(1000);
    }
}

//使用DWT测量函数运行时间
float DTW_Time_DiffMs(volatile uint32_t start, volatile uint32_t stop)
{
    uint32_t diff;
    if(stop > start)
        diff = stop - start;
    else
        diff = stop + 0XFFFFFFFFu - start;
    return (diff / (SystemCoreClock/1000));
}

float DTW_Time_DiffUs(volatile uint32_t start, volatile uint32_t stop)
{
    uint32_t diff;
    if(stop > start)
        diff = stop - start;
    else
        diff = stop + 0XFFFFFFFFu - start;
    return (diff / (SystemCoreClock/1000000));
}