context::regs

Adam Lackorzynski adam at os.inf.tu-dresden.de
Sun May 3 23:29:43 CEST 2015


On Wed Apr 29, 2015 at 14:20:11 +0800, watermirror wrote:
> hi,the implemention of Context::regs() is like this:
> 
> return reinterpret_cast<Entry_frame*>(Cpu::stack_align(reinterpret_cast<Mword>(this + Size)) -1;
> 
> how this algorithm came out?i think the memory of the object is allocated by c++ compiler,  but why '(this + Size)' could get Entry_frame of a thread?

The stacks of the threads have a 2^n size and are size-aligned which
makes such calculations possible. Threads also have their own new
operator which handles this.




Adam
-- 
Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/



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