Extract and Modify Field in a 32-bit Register

Code

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

#define GET_FIELD(reg, pos, mask) \
            ((reg & (mask << pos)) >> pos)
#define SET_FIELD(reg, pos, mask, val) \
            (reg = (((mask & val) << pos) | (reg & ~(mask << pos))) )

/*
 * Function to update the 5-bit field at position 10 by incrementing its value by 1,
 */
uint32_t update_register(uint32_t reg) {
    uint32_t val = 0;
    val = GET_FIELD (reg, 10, 0b11111);
    val = (val < 31) ?
            (val+1) : val;
    SET_FIELD(reg, 10, 0b11111, val);

    return reg;
}

int main() {
    uint32_t reg;
    scanf("%u", &reg);
    uint32_t updated = update_register(reg);
    printf("%u", updated);
    return 0;
}

Solving Approach

The current solution extracts a 5-bit field from position 10 in a 32-bit register, checks if its value is less than 31, and increments it by 1 if so. It then attempts to update the field in the register with the new value using macros for field extraction and setting. However, the macro for setting the field does not properly clear the bits before updating, which may lead to incorrect results. The approach demonstrates conditional field update using bitwise operations, but requires correction for reliable field modification.