Move the cursor up
amount is greater than the maximum move distance then it is internally adjusted to the maximum. If
amount is 0, adjust it to 1.
This unsets the pending wrap state without wrapping.
If the current scroll region is not set or the cursor is above top-most line of current scroll region it may move up until the top of the screen (excluding scroll-back buffer).
amount= 0, is not adjusted to 1.