LED slide

#include "msp.h"

// Define SYSTEM TICK
#define SYSTICK_STCSR (*((volatile unsigned long *)0xE000E010))
#define SYSTICK_STRVR (*((volatile unsigned long *)0xE000E014))
#define SYSTICK_STCVR (*((volatile unsigned long *)0xE000E018))
// Defind state checking
volatile int state = 0;

// Prepare method
void SystemTick_Init(void);
void SystemTick_wait(uint32_t delay);
void Port_Init(void);

// Main loop
int main(void) {
    Port_Init();
    SystemTick_Init();
    while(1){
        SystemTick_wait(3000000);
        while(~P1IN & 0x02){state = 0;}
        while(~P1IN & 0x10){state = 1;}
        if(state == 0){
            P2OUT = P2OUT << 1;
            if(P2OUT == 0x08){P2OUT = 0x01;}
        }else{
            P2OUT = P2OUT >> 1;
            if(P2OUT == 0x00){P2OUT = 0x04;}
        }
    }
}

// Add descript method
void Port_Init(void){
    P1SEL1 = 0x00;
    P1SEL0 = 0x00;
    P2SEL1 = 0x00;
    P2SEL0 = 0x00;
    P1DIR = 0x00;
    P2DIR = 0x07;
    P1OUT = 0x12;
    P2OUT = 0x01;
    P1REN = 0x12;
}

void SystemTick_Init(void){
        SYSTICK_STCSR = 0;
      SYSTICK_STRVR = 0x00FFFFFF;
      SYSTICK_STCVR = 0;
      SYSTICK_STCSR = 0x00000005;
}

// delay parameter is units of the 3MHz clock.
void SystemTick_wait(uint32_t delay){
    SYSTICK_STRVR = delay - 1;
    SYSTICK_STCVR = 0;
    while((SYSTICK_STCSR & 0x00010000) == 0){}
}