Though it is not a course,I would recommend the book, "Computing Systems:A Programmers Perspective" by Randall Bryant and David O' Hallaron. I especially like i

Though it is not a course,I would recommend the book, "Computing Systems:A Programmers Perspective" by Randall Bryant and David O' Hallaron. I especially like its full focus on x86-64, explaining the behaviour of a modern processor, including extensive coverage of floating point functionality, which most introductory books only cover perfunctorily. A rare computer arch book written with programmers as the intended audience.