Replace Bit Field in a 32-bit Register

Code

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

uint32_t replace_field(uint32_t reg, uint32_t val, uint8_t pos, uint8_t len) {
    // Your code here
    // consider inputs are: reg = 0000 0000 0000 0000 0000 0000 1111 1111, val=0000, pos = 4, len = 4
    // creating a 32-bit mask and inserting the given value at the given position
    uint32_t mask = ( val << pos ); // mask = 0000 0000 0000 0000 1111 1111 0000 0000
                                    //                                         4

    int i;
    // make the leading bits as 1 from bit-8 till bit-32 in the mask and make trailing bits as 1 after the
    // inserted value=0000.
    for ( i = (pos + len); i < 32; i++ )
    {
        mask = mask | ( 1 << i ); // mask = 1111 1111 1111 1111 1111 1111 0000 0000
        //                                 31                           8    4
    }
    // make trailing bits from bit-1 till bit-4
    for ( i = 0; i < pos; i++ )
    {
        mask = mask | ( 1 << i );// mask = 1111 1111 1111 1111 1111 1111 0000 1111
        //                                 31                          8    4 3210
    }
    // "AND" operation with register and created mask value will give the desired output value
    return reg & mask; // reg = 0000 0000 0000 0000 0000 0000 1111 1111
    //                   mask = 1111 1111 1111 1111 1111 1111 0000 1111
    //                  AND operation
    //                 result = 0000 0000 0000 0000 0000 0000 0000 1111
}

int main() {
    uint32_t reg, val;
    uint8_t pos, len;
    scanf("%u %u %hhu %hhu", &reg, &val, &pos, &len);
    printf("%u", replace_field(reg, val, pos, len));
    return 0;
}

Solving Approach

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