Your first change

A small, understood HLE contract can make a good first contribution. An unresolved import is a research lead, not proof that returning success will improve compatibility. Use the developer curriculum to turn a hypothesis into evidence.

Step 1 — find what is missing

Run the game with logging to a file and search for stub messages:

kyty_emulator.exe --game "D:\Games\Example" --redzone --printf-direction File --printf-output-file _kyty.txt

The loader logs every import it could not resolve, with the NID and the owning module. A line naming a function the game then calls is your target.

Step 2 — work out what it should do

Combine these sources; none alone proves the complete contract:

1. Call-site evidence. Inspect registers, verified argument memory and how the caller uses results. One call does not reveal every argument, optional field or error path.
2. Symbol and type evidence. A NID database can suggest a name, not prove a signature. Verify parameter count/types, signedness, structure size/offsets and the guest ABI from lawful reference material and code evidence.
3. Behavioral evidence. Specify success, failure, output writes and side effects before coding. Preserve a failing regression case. A guessed value that advances one title is a hypothesis, not a verified implementation.

Step 3 — write it

Add to the appropriate module file — or create one following the template in HLE libraries (a small standalone file such as libCes.cpp is the pattern):

The following is a fictional structural sketch, not a real API contract or copy-ready implementation. Establish size/flags validation, guest-pointer policy, ownership and output semantics for the actual function before using this pattern.

struct ExampleParam {
    uint32_t size;
    uint32_t flags;
    void*    buffer;
};

static int KYTY_SYSV_ABI ExampleGetStatus(const ExampleParam* param, int* out_status) {
    PRINT_NAME();

    LOGF("\t param      = 0x%016" PRIx64 "\n"
         "\t out_status = 0x%016" PRIx64 "\n",
         (uint64_t)param, (uint64_t)out_status);

    if (param == nullptr || out_status == nullptr) {
        return EXAMPLE_ERROR_INVALID_PARAM;
    }
    LOGF("\t size = %" PRIu32 ", flags = 0x%08" PRIx32 "\n", param->size, param->flags);

    *out_status = 0;          // only if zero is established by this API's contract
    return OK;
}

Then register it next to the owning module's entries. The example NID below is a placeholder, not a discovered export:

LIB_DEFINE(InitExample_1) {
    LIB_FUNC("aBcDeFgHiJk", Example::ExampleGetStatus);   // <- the NID from the log
}

Step 4 — verify it is actually reached

Rebuild and check that the import binds to the intended address. A breakpoint or trace can establish whether that path was called. If it was not reached, record it as untested. Neither a resolved slot nor a function-entry log proves correct return values, output bytes or side effects.

Step 5 — prove the guest-visible contract

Keep a test that fails before the change and passes after it. Check normal input, size/flag boundaries, null handling where the contract defines it, output layout and values, error codes and side effects. Use sentinels to detect unintended writes on error; do not dereference arbitrary invalid guest addresses just to add a negative test. Check ownership and concurrency when state survives the call.

Build affected targets and run the focused regression plus adjacent tests. If you run a title, record the exact binary, configuration and route with before/after observations. A unit test, a binding check and game progression are separate evidence. Lab C demonstrates why the return code alone is insufficient.

When it does not bind