I found the -steadykey is very useful, but it is used on keyboard only! Does not affect joystick. I want to use this function on the joystick!
Its detail is: It doesn't send input keys until after zero changes are detected between two frames. This delays the inputs for at least one frame; even if all inputs are correctly seen at once, MAME waits for the next frame to see that all the same keys are still down, before sending to the game. If the keyboard is really slow, OTOH, it might take a couple frames to send the computer which keys are down (and up). In this case, MAME waits until the changes stop coming, however many frames that takes.
I found many fighting games’ moves need badly this function (especially CPS1/CPS2/CPS3 games), if you want to use multiple buttons (A+B+C) consistently (like Zangief ’s spinning punch - Street Fighter 3 's EX moves)，you should open -steadykey.
Could somebody write the code of same function for joystick? I meant why not add some code like '-steadybutton' for joystick? Thanks!