How to get `gcc` to generate `bts` instruction for x86-64 from standard C?
- by Norman Ramsey
Inspired by a recent question, I'd like to know if anyone knows how to get gcc to generate the x86-64 bts instruction (bit test and set) on the Linux x86-64 platforms, without resorting to inline assembly or to nonstandard compiler intrinsics.
Related questions:
Why doesn't gcc do this for a simple |= operation were the right-hand side has exactly 1 bit set?
How to get bts using compiler intrinsics or the asm directive
Portability is more important to me than bts, so I won't use and asm directive, and if there's another solution, I prefer not to use compiler instrinsics.
EDIT: The C source language does not support atomic operations, so I'm not particularly interested in getting atomic test-and-set (even though that's the original reason for test-and-set to exist in the first place). If I want something atomic I know I have no chance of doing it with standard C source: it has to be an intrinsic, a library function, or inline assembly. (I have implemented atomic operations in compilers that support multiple threads.)
