utils

// vi:set ft=cpp: -*- Mode: C++ -*-
/* SPDX-License-Identifier: GPL-2.0-only or License-Ref-kk-custom */
/*
 * Copyright (C) 2013 Technische Universität Dresden.
 */
 
#pragma once
 
namespace cxx {
 
template< typename T > inline
T access_once(T const *a)
{
#if 1
  __asm__ __volatile__ ( "" : "=m"(*const_cast<T*>(a)));
  T tmp = *a;
  __asm__ __volatile__ ( "" : "=m"(*const_cast<T*>(a)));
  return tmp;
#else
  return *static_cast<T const volatile *>(a);
#endif
}
 
template< typename T, typename VAL > inline
void write_now(T *a, VAL &&val)
{
  __asm__ __volatile__ ( "" : "=m"(*a));
  *a = val;
  __asm__ __volatile__ ( "" : : "m"(*a));
}
 
 
}