cua-scroll-up is an interactive compiled Lisp function in `cua-base.el'.

(cua-scroll-up &optional ARG)

Scroll text of current window upward ARG lines; or near full screen if no ARG.
If window cannot be scrolled further, move cursor to bottom line instead.
A near full screen is `next-screen-context-lines' less than a full screen.
Negative ARG means scroll downward.
If ARG is the atom `-', scroll downward by nearly full screen.