cpu.rs

    let value = x.wrapping_sub(y);

    let value_b = value as u8;

    cpu.set_sub(true);
    cpu.set_carry(value & 0x100 == 0x100);
    cpu.set_zero(value_b == 0);
    cpu.set_half_carry((x ^ y ^ value) & 0x10 == 0x10);

    value_b
}

fn add_u16_u16(cpu: &mut Cpu, first: u16, second: u16) -> u16 {
    let first = first as u32;
    let second = second as u32;
    let value = first.wrapping_add(second);

    cpu.set_sub(false);
    cpu.set_carry(value & 0x10000 == 0x10000);
    cpu.set_half_carry((first ^ second ^ value) & 0x1000 == 0x1000);

    value as u16
}