uint32_t转double c代码

可以使用union或者memcpy来实现uint32_t到double的转换。

方法一：使用union

#include <stdio.h>
#include <stdint.h>

typedef union {
    uint32_t i;
    double d;
} uint32_double;

int main() {
    uint32_double ud;
    ud.i = 0x3f800000; // 1.0的uint32_t表示
    printf("%f\n", ud.d);
    return 0;
}

方法二：使用memcpy

#include <stdio.h>
#include <stdint.h>
#include <string.h>

int main() {
    uint32_t i = 0x3f800000; // 1.0的uint32_t表示
    double d;
    memcpy(&d, &i, sizeof(uint32_t));
    printf("%f\n", d);
    return 0;
}

两种方法都可以将uint32_t转换为double。注意在使用union时，需要确保uint32_t和double的大小相同。

相关问题

void button_handler(struct Button* handle) { uint8_t read_gpio_level = handle->hal_button_Level(handle->button_id); //ticks counter working.. if((handle->state) > 0) handle->ticks++; /*------------button debounce handle---------------*/ if(read_gpio_level != handle->button_level) { //not equal to prev one //continue read 3 times same new level change if(++(handle->debounce_cnt) >= DEBOUNCE_TICKS) { handle->button_level = read_gpio_level; handle->debounce_cnt = 0; } } else { //leved not change ,counter reset. handle->debounce_cnt = 0; } /*-----------------State machine-------------------*/ switch (handle->state) { case 0: if(handle->button_level == handle->active_level) { //start press down handle->event = (uint8_t)PRESS_DOWN; EVENT_CB(PRESS_DOWN); handle->ticks = 0; handle->repeat = 1; handle->state = 1; } else { handle->event = (uint8_t)NONE_PRESS; } break; case 1: if(handle->button_level != handle->active_level) { //released press up handle->event = (uint8_t)PRESS_UP; EVENT_CB(PRESS_UP); handle->ticks = 0; handle->state = 2; } else if(handle->ticks > LONG_TICKS) { handle->event = (uint8_t)LONG_PRESS_START; EVENT_CB(LONG_PRESS_START); handle->state = 5; } break; case 2: if(handle->button_level == handle->active_level) { //press down again handle->event = (uint8_t)PRESS_DOWN; EVENT_CB(PRESS_DOWN); handle->repeat++; EVENT_CB(PRESS_REPEAT); // repeat hit handle->ticks = 0; handle->state = 3; } else if(handle->ticks > SHORT_TICKS) { //released timeout if(handle->repeat == 1) { handle->event = (uint8_t)SINGLE_CLICK; EVENT_CB(SINGLE_CLICK); } else if(handle->repeat == 2) { handle->event = (uint8_t)DOUBLe_CLICK; EVENT_CB(DOUBLe_CLICK); // repeat hit } handle->state = 0; } break; case 3: if(handle->button_level != handle->active_level) { //released press up handle->event = (uint8_t)PRESS_UP; EVENT_CB(PRESS_UP); if(handle->ticks < SHORT_TICKS) { handle->ticks = 0; handle->state = 2; //repeat press } else { handle->state = 0; } }else if(handle->ticks > SHORT_TICKS){ // long press up handle->state = 0; } break; case 5: if(handle->button_level == handle->active_level) { //continue hold trigger handle->event = (uint8_t)LONG_PRESS_HOLD; EVENT_CB(LONG_PRESS_HOLD); } else { //releasd handle->event = (uint8_t)PRESS_UP; EVENT_CB(PRESS_UP); handle->state = 0; //reset } break; default: handle->state = 0; //reset break; } }帮我详细注释这段代码

这段代码是一个按键处理函数，主要用于处理按键的状态和事件。下面是对代码的详细注释：

void button_handler(struct Button* handle) { 
    // 读取按键GPIO端口的电平值
    uint8_t read_gpio_level = handle->hal_button_Level(handle->button_id);   
    // 计数器开始工作
    if((handle->state) > 0) handle->ticks++; 

    /*------------按键消抖处理---------------*/
    if(read_gpio_level != handle->button_level) { //如果读到的电平值不同于之前的
        //连续读取3次相同的电平值
        if(++(handle->debounce_cnt) >= DEBOUNCE_TICKS) {
            handle->button_level = read_gpio_level; //更新电平值
            handle->debounce_cnt = 0; //重置消抖计数器
        }
    } else { //如果电平值没有变化，重置消抖计数器
        handle->debounce_cnt = 0;
    }

    /*-----------------状态机处理-------------------*/
    switch (handle->state) {
    case 0: //初始状态
        if(handle->button_level == handle->active_level) { //按键按下
            handle->event = (uint8_t)PRESS_DOWN; //设置按键事件
            EVENT_CB(PRESS_DOWN); //触发事件回调函数
            handle->ticks = 0; //重置计数器
            handle->repeat = 1; //重置按键重复次数
            handle->state = 1; //进入下一个状态
        } else {
            handle->event = (uint8_t)NONE_PRESS; //没有按键按下
        }
        break;

    case 1: //按键按下状态
        if(handle->button_level != handle->active_level) { //按键松开
            handle->event = (uint8_t)PRESS_UP; //设置按键事件
            EVENT_CB(PRESS_UP); //触发事件回调函数
            handle->ticks = 0; //重置计数器
            handle->state = 2; //进入下一个状态
        } else if(handle->ticks > LONG_TICKS) { //按键按下超过长按时间
            handle->event = (uint8_t)LONG_PRESS_START; //设置按键事件
            EVENT_CB(LONG_PRESS_START); //触发事件回调函数
            handle->state = 5; //进入下一个状态
        }
        break;

    case 2: //单次按键按下后的状态
        if(handle->button_level == handle->active_level) { //按键再次按下
            handle->event = (uint8_t)PRESS_DOWN; //设置按键事件
            EVENT_CB(PRESS_DOWN); //触发事件回调函数
            handle->repeat++; //增加按键重复次数
            EVENT_CB(PRESS_REPEAT); //触发按键重复事件回调函数
            handle->ticks = 0; //重置计数器
            handle->state = 3; //进入下一个状态
        } else if(handle->ticks > SHORT_TICKS) { //按键松开超过短按时间
            if(handle->repeat == 1) { //单击事件
                handle->event = (uint8_t)SINGLE_CLICK; //设置按键事件
                EVENT_CB(SINGLE_CLICK); //触发事件回调函数
            } else if(handle->repeat == 2) { //双击事件
                handle->event = (uint8_t)DOUBLE_CLICK; //设置按键事件
                EVENT_CB(DOUBLE_CLICK); //触发事件回调函数
            }
            handle->state = 0; //回到初始状态
        }
        break;

    case 3: //按键重复状态
        if(handle->button_level != handle->active_level) { //按键松开
            handle->event = (uint8_t)PRESS_UP; //设置按键事件
            EVENT_CB(PRESS_UP); //触发事件回调函数
            if(handle->ticks < SHORT_TICKS) { //按键松开时间小于短按时间
                handle->ticks = 0; //重置计数器
                handle->state = 2; //回到单次按键按下后的状态
            } else { //按键松开时间大于等于短按时间
                handle->state = 0; //回到初始状态
            }
        } else if(handle->ticks > SHORT_TICKS){ //按键按下时间大于短按时间
            handle->state = 0; //回到初始状态
        }
        break;

    case 5: //长按状态
        if(handle->button_level == handle->active_level) { //按键继续按下
            handle->event = (uint8_t)LONG_PRESS_HOLD; //设置按键事件
            EVENT_CB(LONG_PRESS_HOLD); //触发事件回调函数
        } else { //按键松开
            handle->event = (uint8_t)PRESS_UP; //设置按键事件
            EVENT_CB(PRESS_UP); //触发事件回调函数
            handle->state = 0; //回到初始状态
        }
        break;

    default: //其他状态，回到初始状态
        handle->state = 0;
        break;
    }
}

union ui64_f64 {uint64_t ui;float64_t f;}; 是什么意思

这个代码定义了一个联合体（union），名为`ui64_f64`。联合体是一种特殊的数据类型，它允许在同一内存空间中使用不同的数据类型。这个联合体包含了两个成员变量：一个是无符号64位整数类型的`ui`，另一个是双精度浮点数类型的`f`。由于这两个成员变量在联合体中占用的内存空间重叠，因此对于同一联合体的不同成员变量的赋值会影响到其他成员变量。

这个联合体的定义可以用于将一个64位无符号整数和一个64位双精度浮点数进行转换，例如：

#include <stdint.h>
#include <stdio.h>

union ui64_f64 {
    uint64_t ui;
    double f;
};

int main() {
    union ui64_f64 u;
    u.f = 3.14159265358979323846;
    printf("double: %f, uint64_t: %lu\n", u.f, u.ui);
    u.ui = 0x40490fdbfffc0000;
    printf("uint64_t: %lu, double: %f\n", u.ui, u.f);
    return 0;
}

这个例子中，首先将双精度浮点数3.14159265358979323846赋值给联合体的`f`成员变量，然后输出这个双精度浮点数和对应的64位无符号整数。接着将一个64位无符号整数0x40490fdbfffc0000赋值给联合体的`ui`成员变量，然后输出这个64位无符号整数和对应的双精度浮点数。可以看到，这个联合体可以方便地进行双精度浮点数和64位无符号整数之间的转换。