Set Specific Bits in a 32-bit Register

Code

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

uint32_t setBits(uint32_t reg, int pos, int len) {
    uint32_t mask = ((1U << len) - 1) << pos;
    return reg | mask;
}

int main() {
    uint32_t reg;
    int pos, len;

    // Input register, position, and length
    scanf("%u %d %d", &reg, &pos, &len);

    // Output modified register
    printf("%u\n", setBits(reg, pos, len));

    return 0;
}

Solving Approach

Create a mask of len bits set to 1:
mask = (1U << len) - 1;

Shift the mask to the target position:
shifted_mask = mask << pos;

Set the bits using OR operation:
result = reg | shifted_mask;