static u16 rng_state = 0;

u32 hash16(u32 input, u32 key) {
    u32 hash = input * key;
    return ((hash >> 16) ^ hash) & 0xFFFF;
}

u16 rng16() {
    rng_state += 0xbadd;
    u32 ret = hash16(rng_state, 0x10de);
    rng_state += ret;
    return ret;
}

u32 rng32() {
    return (rng16() << 16) | rng16();
}