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/* Copyright (C) 2006 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
XXX 64-bit atomic operations can be implemented using
cmpxchg8b, if necessary
*/
// Would it be better to use intrinsics ?
// (InterlockedCompareExchange, InterlockedCompareExchange16
// InterlockedExchangeAdd, InterlockedExchange)
#ifndef _atomic_h_cleanup_
#define _atomic_h_cleanup_ "atomic/x86-msvc.h"
#define MY_ATOMIC_MODE "msvc-x86" ## LOCK
#define make_atomic_add_body(S) \
_asm { \
_asm mov reg_ ## S, v \
_asm LOCK xadd *a, reg_ ## S \
_asm movzx v, reg_ ## S \
}
#define make_atomic_cas_body(S) \
_asm { \
_asm mov areg_ ## S, *cmp \
_asm mov reg2_ ## S, set \
_asm LOCK cmpxchg *a, reg2_ ## S \
_asm mov *cmp, areg_ ## S \
_asm setz al \
_asm movzx ret, al \
}
#define make_atomic_swap_body(S) \
_asm { \
_asm mov reg_ ## S, v \
_asm xchg *a, reg_ ## S \
_asm mov v, reg_ ## S \
}
#ifdef MY_ATOMIC_MODE_DUMMY
#define make_atomic_load_body(S) ret=*a
#define make_atomic_store_body(S) *a=v
#else
/*
Actually 32-bit reads/writes are always atomic on x86
But we add LOCK here anyway to force memory barriers
*/
#define make_atomic_load_body(S) \
_asm { \
_asm mov areg_ ## S, 0 \
_asm mov reg2_ ## S, areg_ ## S \
_asm LOCK cmpxchg *a, reg2_ ## S \
_asm mov ret, areg_ ## S \
}
#define make_atomic_store_body(S) \
_asm { \
_asm mov reg_ ## S, v \
_asm xchg *a, reg_ ## S \
}
#endif
#define reg_8 al
#define reg_16 ax
#define reg_32 eax
#define areg_8 al
#define areg_16 ax
#define areg_32 eax
#define reg2_8 bl
#define reg2_16 bx
#define reg2_32 ebx
#else /* cleanup */
#undef reg_8
#undef reg_16
#undef reg_32
#undef areg_8
#undef areg_16
#undef areg_32
#undef reg2_8
#undef reg2_16
#undef reg2_32
#endif
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