sawtooth function on simulink for control desk

[soundara]

Hi there,
Matlab 7.02 apparently doesn't have the sawtooth function(i actually need triangular wave - i use the sawtooth function with the factor 0.5 to make a triangular wave out of a sawtooth. can someone tell me how I can generate the wave on simulink using mathematical functions. I have to run o the model on dspace control desk which means that there are limitations on using matlab functions. thank you.