title: The PUSHAD POPAD or using the "USES" operator
body: <p>I am a new user to assembly language and am using the book assembly language by kip irvine, and he talks about using the PUSHAD AND POPAD to save the general registers on the stack. Irvine said if you are writing procedures that modify any of the registers you need to use PUSHAD AND POPAD to save and restore the registers after you have called the procedure.</p>
  
  <p>I wanted to know is it better and more correct and efficient to use the "USES" operator to  just save and restore the registers you use within your procedure (e.g. if you only use the EAX and ECX registers) , or should you just save and restore all the registers.</p>