gc-alloc 0.2.1

/*
 * Copyright (c) 2003 Hewlett-Packard Development Company, L.P.
 * Copyright (c) 2009-2021 Ivan Maidanski
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#if !defined(AO_ATOMIC_OPS_H) || defined(AO_ATOMIC_OPS_INCLUDED)
# error This file should not be included directly.
#endif

#include "../all_aligned_atomic_load_store.h"

#if !defined(AO_ASSUME_VISTA) && _MSC_VER >= 1910
  /* Visual Studio 2017 (15.0) discontinued support of Windows XP.  */
  /* We assume Windows Server 2003, Vista or later.                 */
# define AO_ASSUME_VISTA
#endif

#if !defined(AO_ASSUME_WINDOWS98) \
    && (defined(AO_ASSUME_VISTA) || _MSC_VER >= 1400)
   /* Visual Studio 2005 (MS VC++ 8.0) discontinued support of Windows 95. */
# define AO_ASSUME_WINDOWS98
#endif

#if !defined(AO_USE_PENTIUM4_INSTRS) && _M_IX86_FP >= 2 /* SSE2 */
  /* "mfence" is a part of SSE2 set (introduced on Intel Pentium 4).    */
# define AO_USE_PENTIUM4_INSTRS
#endif

#define AO_T_IS_INT

#ifndef AO_USE_INTERLOCKED_INTRINSICS
  /* Interlocked primitives (Inc, Dec, Xchg, Add) are always available. */
# define AO_USE_INTERLOCKED_INTRINSICS
#endif
#include "common32_defs.h"

#ifdef AO_NO_ASM_XCHG
  /* Use the default implementation based on test_and_set_full. */
#else

  /* As far as we can tell, the lfence and sfence instructions  */
  /* are not currently needed or useful for cached memory       */
  /* accesses.  Unfortunately mfence doesn't exist everywhere;  */
  /* IsProcessorFeaturePresent(PF_COMPARE_EXCHANGE128) is       */
  /* probably a conservative test for it.                       */

# ifdef AO_USE_PENTIUM4_INSTRS
    AO_INLINE void
    AO_nop_full(void)
    {
      __asm { mfence }
    }
#   define AO_HAVE_nop_full
# else
    /* We could use the cpuid instruction.  But that seems to   */
    /* be slower than the default implementation based on       */
    /* test_and_set_full.  Thus we omit that bit of             */
    /* misinformation here.                                     */
# endif
#endif /* !AO_NO_ASM_XCHG */

#if !defined(AO_NO_ASM_XADD) && !defined(AO_HAVE_char_fetch_and_add_full)
  AO_INLINE unsigned char
  AO_char_fetch_and_add_full(volatile unsigned char *p, unsigned char incr)
  {
    __asm
    {
      mov al, incr
      mov ebx, p
      lock xadd byte ptr [ebx], al
    }
    /* Ignore possible "missing return value" warning here.     */
  }
# define AO_HAVE_char_fetch_and_add_full

  AO_INLINE unsigned short
  AO_short_fetch_and_add_full(volatile unsigned short *p, unsigned short incr)
  {
    __asm
    {
      mov ax, incr
      mov ebx, p
      lock xadd word ptr [ebx], ax
    }
    /* Ignore possible "missing return value" warning here.     */
  }
# define AO_HAVE_short_fetch_and_add_full
#endif /* !AO_NO_ASM_XADD */

#ifndef AO_HAVE_test_and_set_full
# ifdef AO_NO_ASM_XCHG
#   include "../test_and_set_t_is_ao_t.h"
# else
#   include "../test_and_set_t_is_char.h"
# endif

  AO_INLINE AO_TS_VAL_t
  AO_test_and_set_full(volatile AO_TS_t *addr)
  {
#   ifdef AO_NO_ASM_XCHG
      return _InterlockedExchange((long AO_INTERLOCKED_VOLATILE *)addr,
                                  AO_TS_SET);
#   else
      __asm
      {
        mov     eax,0xff                ; /* AO_TS_SET */
        mov     ebx,addr                ;
        xchg    byte ptr [ebx],al       ;
      }
      /* Ignore possible "missing return value" warning here. */
#   endif
  }
# define AO_HAVE_test_and_set_full
#endif

#if defined(_WIN64) && !defined(CPPCHECK)
# error wrong architecture
#endif

#ifdef AO_ASSUME_VISTA
# include "../standard_ao_double_t.h"

  /* Reading or writing a quadword aligned on a 64-bit boundary is      */
  /* always carried out atomically (requires at least a Pentium).       */
# define AO_ACCESS_double_CHECK_ALIGNED
# include "../loadstore/double_atomic_load_store.h"

  /* Whenever we run on a Pentium class machine, we have that certain   */
  /* function.                                                          */
# pragma intrinsic (_InterlockedCompareExchange64)

  /* Returns nonzero if the comparison succeeded.       */
  AO_INLINE int
  AO_double_compare_and_swap_full(volatile AO_double_t *addr,
                                  AO_double_t old_val, AO_double_t new_val)
  {
    AO_ASSERT_ADDR_ALIGNED(addr);
    return (double_ptr_storage)_InterlockedCompareExchange64(
                                        (__int64 volatile *)addr,
                                        new_val.AO_whole /* exchange */,
                                        old_val.AO_whole) == old_val.AO_whole;
  }
# define AO_HAVE_double_compare_and_swap_full
#endif /* AO_ASSUME_VISTA */

/* Real X86 implementations, except for some old WinChips, appear       */
/* to enforce ordering between memory operations, EXCEPT that a later   */
/* read can pass earlier writes, presumably due to the visible          */
/* presence of store buffers.                                           */
/* We ignore both the WinChips, and the fact that the official specs    */
/* seem to be much weaker (and arguably too weak to be usable).         */
#include "../ordered_except_wr.h"