Hi, Thanks for responding to my previous mail. A few more queries a. What is the use of adding format specifiers in inline assembly like asm volatile("ld%U1%X1 %0,%1":"=r"(ret) : "m"(*ptr) : "memory"); b. using m or Z with a memory address. I tried replacing m/Z but no change Is there some guideline ? gcc documentation says Z is obsolete. Is m/Z replaceable ? - Manish