How to pack numbers without bit operations?

Question

Mathematics

There are 4 bytes of space. There are several polbyte numbers. How to pack half-byte numbers into a 4-byte number using arithmetic operations?

Answer 1

How to pack half-byte numbers into a 4-byte number using arithmetic operations?

Multiply/divide by 16 ⁱ and add.
For example:

uint32_t put_nibble(uint32_t v, int nibble_index, uint32_t nibble)
{
    uint32_t p = 1;
    uint32_t r;
    int i;
    for (i = 0; i < nibble_index; ++i)
        p *= 16;
    r = (v % p) + (nibble * p);
    if (nibble_index < 7)
        r += (v / (p * 16)) * p * 16;
    return r;
}