PLEASE ADD COMMENTS TO EVERY LINE OF THE CODE AND FIX IT AND READ WHATS IN BOLD!

Question

PLEASE ADD COMMENTS TO EVERY LINE OF THE CODE AND FIX IT AND READ WHATS IN BOLD!!!

#include <msp430g2553.h>

/*
* Fix this code! You may NOT delete or add code, you may only change values being stored in a variable or register.
*/

void DELAY();
unsigned int CLS(unsigned int x);
unsigned int CRS(unsigned int x);

int main(void) {
WDTCTL = WDTPW | WDTHOLD;

volatile unsigned int m = 1;
volatile unsigned int s = 0;
volatile unsigned int p = 65535;

P1DIR |= m;

while(s)
{
   p = CRS(p);
   P1OUT = p;
   DELAY();
}
}

void DELAY(){
   volatile unsigned int i = 25;
   volatile unsigned int j = 0;
   volatile unsigned int k = 1;
   volatile unsigned int l = 0;
  
   for(; i > 0; i--)
   {
       j += 2;
       k += 2;
   }

   l = CLS(j + k);
}

unsigned int CLS(unsigned int x){
   return (x << 1) | (x >> 15);
}

unsigned int CRS(unsigned int x){
   return (x >> 1) | (x << 15);
}

Explanation / Answer

#include <msp430g2553.h> //including the directory here means the directory itself contains some logic ,so we are just using it

void DELAY(); //declaring a function name as DELAY with return type as void ,means this function don't return a value
unsigned int CLS(unsigned int x);//declaring CLS function by passing an unsigned int as an argument to it and unsigned int as return type that returns an unsigned int
unsigned int CRS(unsigned int x); //declaring CRS function by passing an unsigned int as an argument to it and unsigned int as return type that returns an unsigned int

int main(void) { // main function with int as return type
WDTCTL = WDTPW | WDTHOLD; //WDTCTL a variable that holds a value with logical condition

volatile unsigned int m = 1; // here declaring and initialising three variables m,s and p
volatile unsigned int s = 0;
volatile unsigned int p = 65535;

P1DIR |= m; //here assigning that initialized "m" value to P1DIR variable

while(s) //while loop with passing initialized variable "s"
{
   p = CRS(p); //here passing "p" value to CRS function and storing that returned value from that funtion to a variable"p"
   P1OUT = p; // above returned value to P1OUT variable
   DELAY();// caling delay() function
}
}

void DELAY(){ // implementation of delay() function
   volatile unsigned int i = 25; // declaring and initializing four variables i,j,k,l
   volatile unsigned int j = 0;
   volatile unsigned int k = 1;
   volatile unsigned int l = 0;
  
   for(; i > 0; i--) // for loop with iteration i=25 and i>0 which is true so j and k values increment by 2

so in first iteration the values of j=2,k=3 and then i value decrements by 1 so i =24

this process continues till the condition becomes false
   {
       j += 2;
       k += 2;
   }

   l = CLS(j + k); // calling CLS function and storing that returned value from that function into "l"

}

unsigned int CLS(unsigned int x){ //implementation of CLS function
   return (x << 1) | (x >> 15); //to return a value based on the "x" value ,a check with comparision of value each time with x value
}

unsigned int CRS(unsigned int x){    //implementation of CLS function
   return (x >> 1) | (x << 15);   //to return a value based on the "x" value ,a check with comparision of value each time with x value
}

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