I have a time critical application where I have to process an external interrupt request. When the interrupt occurs, I have to read a port and store this data pointed by a pointer. In order to reduce the time taken by pushes and pops, I would like to bind a register pair to a char pointer. My search for examples has not yielded any results. I have tried something like "unsigned char *ptr asm ("x")" but this is throwing out an error. Can some one show me an example on how to achieve this? Thank you.