Friends let me see this code

On the weekend , A wechat friend asked me to look at a piece of code

Before writing the following article , Let me start with a few words

Writing code is a very interesting thing , At the same time, it is also a matter that we need to take seriously , I don't think it's necessary to write the code as unreadable as the great God , But at least be logical , Cannot appear confusion Don't know which What happened .

Last year , I am also constantly improving my programming ability , Previous work , Many of them do things like processing systems and drivers , But the actual application programming does not have a strong foundation . Is also constantly learning and moving forward , I also thank my friends and colleagues for their help and support .

——

This code looks like this

static unsigned short timer_tick_cnt = 0;


static ___interrupt USER_TIMER void timer_isr(void)// Interrupt service function 
{
    if (TMR->CON & BIT(15)) // Timer overflow interrupt flag bit 
    {
        TMR->CON |= BIT(14);// Clearing and interrupting 
        ///putchar('@');
        //todo, Interrupt function execution program ...
        timer_tick_cnt++;
    }
}

static unsigned short timer_tick_get_current_timer(void)
{
 unsigned short timer_tick_count = timer_tick_cnt;
    return timer_tick_count;
}

unsigned short usRecord = 0;

unsigned char timer_tick_timeout_wait(unsigned short *p_var, unsigned short timeout)
{
    if( timer_tick_get_current_timer() - *p_var  < timeout )
    {
        ///usRecord = timer_tick_get_current_timer();
        ///printf("=======rec=%d,*p_var=%d=====\n",usRecord,*p_var);
        ///printf("====TIMER return 0====\n");
        return 0;
    }

    *p_var  = timer_tick_get_current_timer();
    ///usRecord///printf("====TIMER return 1====\n");
    return 1;
}
unsigned short testTimer = 0;
#define TIME_TICK_1MS_1S 1000
void testHandler(void)
{
 if(timer_tick_timeout_wait(&testTimer,TIME_TICK_1MS_1S))//1ms Interrupt overflow of , so 1000 by 1s
 {
  printf("helloworld\n");// The problem is if timer_tick_timeout_wait Parameters of timeout Defined as unsigned short, In about 65s(65535ms) This function always returns 0 Instead of returning 1,unsigned int normal 
 }
}
int main(void)
{
 timerInit();//1ms The timer is interrupted , This function is not a problem , The problem lies below 
 while(1)
 {
  testHandler();
 }
}

This is the original code , I didn't make any changes .

The problem he described in the code is relatively clear

// The problem is if timer_tick_timeout_wait Parameters of timeout Defined as unsigned short, In about 65s(65535ms) This function always returns 0 Instead of returning 1,unsigned int normal

Careful people will find a problem

this timer_tick_cnt Damn variable keeps increasing

I wrote an article before , It's the timestamp problem in the kernel , If there is a problem with the variable definition of saving timestamp , That may also cause time problems .

That's why he found something wrong with his code .

——

Let me talk about other situations

The original intention of the system he designed is that the system timer executes a function after a specified time , But directly take the variables in the timer to the outside to judge , It's not very good here .

The timer should only complete the timed things , As for the time , Just tell other tasks outside , This can achieve high cohesion .

Variable timer_tick_cnt Operate in other places , It will be very uncomfortable to check the following problems .

——

Variable name 、 Function name 、 Code style.

It's just ugly , Underline some places 、 Humps are used in some places .

And the execution of this function , I can't understand it

CPU That's how you're tired .

About variable and function naming website , I recommend this , This website is very suitable for us

https://www.chtml.cn

It's not much better than you think .

——

The meaning of macros is not clear

Naming macros like this is very bad , First, 1MS again 1S, So what is this macro , It's hard to understand the meaning without looking at the code .

If I were , I'll show you what this macro does , But then add MS, Because this event is MS Time for .

——

You may also find the naming of functions , Some are humps , Some underline .

That's not the point , The key is that the intention of some functions is not clear , I don't know what the function is .

These are my own personal views

I think writing code is to treat a work of Art , Do this thing well , Well done , It's a pleasure for us .

Let's encourage it ！