void glowled();
void scan();

volatile bool switchon = false;  // Initially LEDs are not glowing

void setup() {

  volatile char *dir = (char *)0x30;
  volatile char *dirsw = (char *)0x107;
  *dir = 0xFF;     // Set all pins as output for LEDs
  *dirsw = 0x00;   // Set all pins as input for switch
}

void loop() {
  glowled();
}

void glowled() {
  volatile char *out = (char *)0x31;
  static volatile long i = 0;  // Static to keep the state between function calls
  
  while (true) {  // Continuous loop to keep the glow process running
    scan();  // Always check if the button is pressed
    
    if (switchon) {
      *out = 0x01 << i;  // Light up the current LED
      delay(250);        // Add a small delay to make the LED visible
      
      i++;               // Move to the next LED
      if (i > 7) i = 0;  // Wrap around after the 8th LED
    } else {
      // If the switch is off, hold the current LED state
      
      
      // Wait until the switch is pressed again to continue
      while (!switchon) {
        scan();          // Keep checking for the switch press
        delay(50);       // Small delay to avoid rapid polling
      }
    }
  }
}

void scan() {
  volatile char *swin = (char *)0x106;

  // Check if the button is pressed (active-high)
  if (*swin & 0x01) {
    delay(25);
    switchon = !switchon;  // Toggle the `switchon` state
    while (*swin & 0x01);  // Wait for the button to be released
  }
}