This is not an easy task, as I have already mentioned in my comments to your question you should know that drawing these objects on screen is a tough job and you need to understand the concepts of graphics, and how to draw the stuff on screen using the pixels and many more. If you were to use a high-level language, such as Java or Visual C# they would allow you to use their namespaces and classes to work with graphics just like calculating a few values and print it to the screen.
But, since assembly is a low-level language, there is no graphics stuff built right into it that would let you draw a circle and if it did, the radius to be a variable would take another file of code. And you're asking for a machine language code (your last comment) you seem to be confused about what you're doing and which language you're going to use and what is the scenario around. That is why, I am not going to confuse you any further.
There is
another question[
^], to which is an
answer[
^] that I would like you to read. If, doesn't include the code to build and draw that circle on the screen. But it
might give you an idea to draw the circle using Assembly language, using some different algorithms.
Again, to work with graphics, you should use a high-level language. Working in low-level for drawing purposes is not an efficient way.