On Wed, Sep 26, 2012 at 11:54 AM, ali hagigat <hagigatali@xxxxxxxxx> wrote: > NOP has three main functions: > 1) for delay > 2) for alignment and atomic operations > 3) for correcting the functionality of the CPU pipeline > > Sometimes GCC itself adds extra NOPs to satisfy 3. That's for gcc generated NOP, agree on that. I thoughtthe nop I saw was of that kinds. As Kalle pointed out, some C construct can also 'reserve' place holder to be patched runtime, typically allowing spot for tracepoint, or enablement of runtime test (assertion, debug print, etc), the patch is generally a nop (on x86 variable length). In this case this is not a gcc generated nop. Cheers, Phi
