Sin calculation

- The crypto code means generating stream of data encoded with a certain kind of calculation so then the real data coming out from a microprocessor are unreadable. This kind of encoding is done with a public key and private key criteria to generate protected trasmission. To do that the two main formula used are sin and cosin. It is true that the cosin is the 90° phaseshift respect the sin but in this case I need a precise calculation otherwise the data decoder will re-generate a wrong message.

I use the ST72F521R9 microprocessor. I need to calculate the trigonometrical formula x=sin(y) using the assembly code of the ST7. Is there anyone who has such routine either in souce code or as object file?

Thank you for the help.