Short form: everything we've done, up to but not including pipelining.
Long form:
Conversion between decimal and IEEE floating point format
Arithmetic operations (add, subtract, multiply, divide)
Special cases (infinity, denorms, 0)
Instruction Formats
Semantics of instructions on cheat sheet
The emphasis will be on the first and third parts. You can definitely expect to do a number conversion either from or to IEEE format, and you can definitely expect to do an arithmetic operation. You can also expect to do something like tracing the flow of an instruction through the datapaths, or modifying the datapaths.
I have an old exam archive here. You should be able to access all of them; if any are protected let me know and I'll open them up.