19. Extract a Bit Field from a 32-bit Register

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

uint32_t extract_field(uint32_t reg, uint8_t pos, uint8_t len) {
    
    reg = ( reg >> pos );
    
    uint32_t mask = 0;

    for( uint32_t i = 0 ; i<len ; i++ )
    {
        mask |= ( 1U << i) ; 
    }

    return reg & mask;
    
}

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