GCC-Veterans, I've written hand-written assembly for couple of commonly used function in my module with an intent of having a very highly optimized version of the same taking into consideration cache, process cache-lines et al. I'm not an ABI expert and I wanted to know the calling convention usually followed to pass the parameters in register to the function ? How to let the GCC know what function parameter have to be passed in a specific register ? Thanks, Vijay Nag