The built-in functions include round, floor, ceil, and trunc. Trunc rounds towards zero. For floats, the behavior of trunc is equivalent to the following:
float func trunc(float x) if x >= 0 return floor(x) else return ceil(x) endif endfunc
There is no equivalent function with < instead of >. In mathematics, I haven't even found a name for this. The best name that I could come up is "elong", a shortened version of elongate, as truncate is short for truncate.