Rotate Left in an 8-bit Register

Code

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

uint8_t rotate_left(uint8_t reg, uint8_t n) {
    // Your code here
    uint8_t mask = ((uint8_t)pow(2,n) -1) << (8-n);
    uint8_t val = (reg & mask) >> (8-n);
    reg = (reg << n)|val;
    return reg;
}

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

Solving Approach