Hi! I created a library for a cross-platform C compiler to target old computers called cc65. The library is called CBMSimpleIO and replaces printf() with much more efficient text screen/keyboard functions. It can save about 2k on its target systems. 2k is not much but it helps on older systems. Now, I want to implement it for the DOS platform. I have Turbo C, Open Watcom C and the NASM assembler. I have two questions: 1. Should I? 2. How do I interface C with assembler? I also want it for __fastcall functions.