Bit Operations using Macros

Code

#include <stdio.h>
#include <stdint.h>

// Define bitwise macros here
#define SET_BIT(r, b)    ((r) |= (1 << (b)))
#define CLEAR_BIT(r, b)    ((r) &= ~(1 << (b)))
#define TOGGLE_BIT(r, b)    ((r) ^= (1 << (b)))

uint8_t modify_register(uint8_t reg) {
    // Apply operations in order
    
    // 1. set bits 2 and 7
    SET_BIT(reg, 2);
    SET_BIT(reg, 7);

    // 2. clear bit 3
    CLEAR_BIT(reg, 3);

    // 3. toggle bit 5
    TOGGLE_BIT(reg, 5);

    return reg;
}
/*
// my code
uint8_t modify_register(uint8_t reg) {
    // Apply operations in order
    
    // 1. set bits 2 and 7
    reg |= ((1 << 2) | (1 << 7));

    // 2. clear bit 3
    reg &= ~(1 << 3);

    // 3. toggle bit 5
    reg ^= (1 << 5);

    return reg;
}
*/

int main() {
    uint8_t reg;
    scanf("%hhu", &reg);
    printf("%u", modify_register(reg));
    return 0;
}

Solving Approach

It is kind of real HW register settings

• use #define to set, clear, toggle registers