Extract and Modify Field in a 32-bit Register

Code

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

uint32_t update_register(uint32_t reg) {
    uint32_t mask = 0x1F << 10;
    uint32_t field = (reg >> 10) & 0x1F;

    if (field < 31)
       field += 1;

    reg = (reg & ~mask) | (field << 10);
    return reg;
}

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

Solving Approach

• Create mask for the target field (5 bits at position 10):
  mask = 0x1F << 10
• Extract field value from the register:
  field = (reg >> 10) & 0x1F
• Increment the field if less than 31:
  if (field < 31) field += 1
• Clear original bits in the register:
  reg = reg & ~mask
• Insert updated field back:
  reg = reg | (field << 10)
• Return updated register.