Bitwise operation to toggle bits in memory.

bitwise.c

#include <stdint.h>

#define LED_RED   (1U << 1) // 1st bit, 0x2
#define LED_BLUE  (1U << 2) // 2nd bit, 0x4
#define LED_GREEN (1U << 3) // 3rd bit, 0x8

int main() {
    uint32_t reg = 0x800;

    reg |= LED_RED; // set individual bits using the bitwise OR
    reg |= LED_BLUE;
    reg |= LED_GREEN;

    // clear individual bits using bitwise AND and NOT
    // combining all bits will work also:
    // 0b1000 | 0b0100 | 0b0010 = 0b1110
    // mask = ~0b1110 = 0b0001
    // reg (0x80E) &= mask = 0x800 - all bits off
    reg &= ~(LED_RED | LED_BLUE | LED_GREEN);

    // in fact, the compiler will generate a better assembly code
    // for the last instruction, simply using bit clear operation
    return 0;
}