EMU48 Remove Input Buffer/Lag?

[Eric Rechlin]

It is kind of annoying. I primarily use Emu48 with a 48GX ROM and a 50g ROM, and both have their own annoyances with the keyboard.

With the 48G series ROM, there is the input lag that you mention. It never misses keystrokes, but there's always a delay even when running at full speed on my rather fast (i9-13900K) PC. Now, this can be solved by switching to a 49/50 series ROM.

However, with the 49/50 ROM, there is no input lag, but keystrokes are missed. I am not talking about missing strokes when the same key is pressed twice in quick succession due to software debouncing found in the 49/50 that the 48 doesn't have (that's easily resolved by setting ->KEYTIME to something low like 200). The problem is that when you are at the stack with no input line, if you press three keys in quick succession, it only registers the first one. If you press four keys in quick succession it registers the first and fourth. If you press even more keys it registers the first and the fourth and subsequent ones, but still not the second and third. However, if you only press two in quick succession it reads both. It's all very strange. But then once the input line is up and the cursor is blinking, it reads every keystroke no matter how fast you type. So if you press one key, it works, and then press 3 more keys in quick succession and it reads all three of those too. I thought maybe it was a relative of the so-called "busy bug" so I tried turning on the ticking clock but that doesn't fix it so it's probably something unrelated. I think this is probably a bug in the underlying 49/50 ROM and not an emulator bug, but it's frustrating.

Example:

Go to the stack and press 1 2 as fast as you can. You get 12. Press 1 2 3 as fast as you can. You get 1. Press 1 2 3 4 as fast as you can. You get 14. Press 1 2 3 4 5 6 as fast as you can. You get 1456. This is consistent, every time. But press 1, wait a bit, and press 2 3 and you get 123. Press 1, wait a bit, and press 2 3 4 5 6 and you get 123456.

So basically, when the calculator switches from the stack mode to the input line mode, which happens after the first keystroke, if the subsequent keystrokes come too quickly, the next two keystrokes are lost, but if you only press one subsequent keystroke then it works. Very strange.