tst-stack-align.h

glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的好资料

/* Copyright (C) 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <stdio.h>
#include <stdint.h>
#ifndef __SSE__
#include_next <tst-stack-align.h>
#else
#include <xmmintrin.h>

#define TEST_STACK_ALIGN() \
  ({									     \
    __m128 _m;								     \
    double _d = 12.0;							     \
    long double _ld = 15.0;						     \
    int _ret = 0;							     \
    printf ("__m128:  %p %zu\n", &_m, __alignof (__m128));		     \
    if ((((uintptr_t) &_m) & (__alignof (__m128) - 1)) != 0)		     \
      _ret = 1;								     \
									     \
    printf ("double:  %g %p %zu\n", _d, &_d, __alignof (double));	     \
    if ((((uintptr_t) &_d) & (__alignof (double) - 1)) != 0)		     \
      _ret = 1;								     \
									     \
    printf ("ldouble: %Lg %p %zu\n", _ld, &_ld, __alignof (long double));    \
    if ((((uintptr_t) &_ld) & (__alignof (long double) - 1)) != 0)	     \
      _ret = 1;								     \
    _ret;								     \
    })
#endif