The Setup-Relationship Equation given on page 174 of (UG612) is incorrect.
What is the correct equation?
The correct Setup-Relationship Equation can be written by replacing (-TOFFSET_IN_BEFORE) with TOFFSET_IN_BEFORE in the given equation.
So the correct equation can be written as
TDATA + TSETUP - TCLOCK <= (-TOFFSET_IN_BEFORE)
TOFFSET_IN_BEFORE <= TCLOCK - TDATA - TSETUP