Syscall index: 0x12C6
Function signature: int Keyboard_PutKeycode(int x, int y, int keycode)
Injects a key code into a key buffer.
If both x and y are below zero, keycode is injected into the GetKey buffer and its next call will return keycode. This works even on the "fx-CG10/20 Manager" emulator.
If x and y are equal or higher than zero, they will be treated as matrix codes and injected into different lower level key buffer(s), used by lower-level keyboard reading syscalls, and keycode will be ignored.