Problem with programming PIC 16f84a

I have got the following problem.
I am supposed to program a PIC to take input from 4 diffrent outputs and create a different melody for each button for output. So far i have learnt the basic program template and commands but i can seem to figure out how to make the speaker connected to the Output of the PIC produce different tones can anyone help. I already checked this page but its in C and i need to know how to do it in assembly, the reason is that i am doing this from a laboratory and dont have a C compiler.
Please help

If that's the type of tune you want to use, disassemble the HEX code, and manually edit the resulting assembler. However, the C compiler used has a free trial version, which does all you require anyway.