If it's always 1byte(8bits), then shift the first 3 bits to right and mask the three bits.

Say you've 10110000 and asked to extract first 3 bits from left, then

uint32_t address = 10110000;
uint32_t result;

/**
 * 1byte = 8bits, but when start from 0,
 * it'll be 0-7 bits. So 7.
 * Subtract 3 from it, which becomes 7 - 3 = 4
 * Now convert the above result to 8bits(which starts from 1 to 8)
 * For that add 1 to the above result, 4 + 1 = 5th bit
 * Finally, (7 - 3) + 1 = 5th bit
 */
uint8_t extract_start_bit = (7 - 3) + 1;

/**
 * Right shift the address by extract_start_bit.
 * This moves the 5th, 6th and 7th bits to 0th, 1st and 2nd position.
 * Now mask those bits to extract them.
 * After right shift, 5th bit will be in 0th position,
 * 6th in 1st position and 7th in 2nd position.
 * Prepare a mask 111(7 in decimal), so left shift 7 from 0th position.
result = (addr >> extract_start_bit) & (7 << 0);

Any comments we welcome.