Implement bit variable inversion function

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In the 51 single-chip microcomputer, there is a special variable sbit (bit variable)

It is very easy to use it to do a variable inversion, nuber=!nuber does it.

Why do we need this feature?

Let's look at a program

Assume that LED is a light, LED=1 is on, LED=0 is off.

So I want it to flash for 200 milliseconds.

while(1)

{

  LED=!LED;

  delay_ms(200);

}

This is how the 51 single-chip microcomputer is written.

This is not advisable in C language, because we cannot map a certain bit. (In fact, I don't know how to map a certain bit of the register to operate)

So usually I use the functions LED_ON(), LED_OFF()

In this case, the procedure should be like this

while(1)

{

  LED_ON()

  delay_ms(100);

  LED_OFF();

    delay_ms(100);

}

Then I have a lot of other things in my while(1), and I have to run it every 10ms, so 51 should achieve 200ms flashing like this

while(1)

{

  n++;

  if(n==20){

    n=0;

            LED=!LED;

    }

  delay_ms(10);

}

It's also very simple, but what about the stm32 without bit variables? Shouldn't the program be rethought?

I'll provide a little method below

(1)

flag=1; //The flag variable should be

while(1)

{

  n++;

  if(n==20){

            n=0;

   if(flag==1)

LED_ON();

   else LED_OFF(); 

flag*=-1 //Every time you multiply by -1, it actually changes from 1 to -1 and then to 1

    }

  delay_ms(10);

}

(2)

flag=1; //The flag variable should be

while(1)

{

  n++;

  if(n==20){

            n=0;

   if((flag&0x1)==1)

LED_ON();

   else LED_OFF(); 

        flag=!flag; //This is the same  

    }

  delay_ms(10);

}

Of course, there are many other ways to implement it, which are not listed here.