This is disputed.
Shulchan Arukh, Orach Chayyim 307:17:
אָסוּר לִלְמֹד בְּשַׁבָּת וְיוֹם טוֹב, זוּלַת בְּדִבְרֵי תּוֹרָה; וַאֲפִלּוּ בְּסִפְרֵי חָכְמוֹת אָסוּר; וְיֵשׁ מִי שֶׁמַּתִּיר, וְעַל פִּי סְבָרָתוֹ מֻתָּר לְהַבִּיט באצטרלו''ב בְּשַׁבָּת, וּלְהָפְכָהּ וּלְטַלְטְלָהּ כְּדִלְקַמָּן סי' ש''ח.
My loose translation:
One should not learn anything on SHabbat except Torah related matters. Even studying books of wisdom (I assume this means "adages" or something similar?) is forbidden. But some say that is permitted, and according to them one may use an astrolabe on Shabbat.
On the other hand, it seems that if the sole purpose of studying is for an exam that will occur after Shabbat, then, this may be a prohibition of hachanah - preparing on Shabbat for a weekday. That's also debated. See item #14 in Halachipedia along with its footnote.