Question

I’d like to increment the 64bit(long type in C++) counter in inline assembly atomically. I know how to do that on 32bit value(int):

asm volatile("lock; incl %0" : "=m" (val) : "m"(val));

But I have no idea how to perform that on long value.

Answer 1

moved self answer from the question to an answer

It was quite easy, but I haven’t been familiar with x86-64.

asm volatile("lock; incq %0" : "=m" (val) : "m"(val));