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96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/* Copyright (C) 2006 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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XXX 64-bit atomic operations can be implemented using
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cmpxchg8b, if necessary
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*/
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// Would it be better to use intrinsics ?
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// (InterlockedCompareExchange, InterlockedCompareExchange16
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// InterlockedExchangeAdd, InterlockedExchange)
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#ifndef _atomic_h_cleanup_
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#define _atomic_h_cleanup_ "atomic/x86-msvc.h"
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#define MY_ATOMIC_MODE "msvc-x86" LOCK
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#define make_atomic_add_body(S) \
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_asm { \
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_asm mov reg_ ## S, v \
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_asm LOCK xadd *a, reg_ ## S \
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_asm movzx v, reg_ ## S \
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}
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#define make_atomic_cas_body(S) \
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_asm { \
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_asm mov areg_ ## S, *cmp \
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_asm mov reg2_ ## S, set \
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_asm LOCK cmpxchg *a, reg2_ ## S \
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_asm mov *cmp, areg_ ## S \
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_asm setz al \
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_asm movzx ret, al \
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}
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#define make_atomic_swap_body(S) \
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_asm { \
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_asm mov reg_ ## S, v \
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_asm xchg *a, reg_ ## S \
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_asm mov v, reg_ ## S \
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}
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#ifdef MY_ATOMIC_MODE_DUMMY
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#define make_atomic_load_body(S) ret=*a
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#define make_atomic_store_body(S) *a=v
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#else
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/*
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Actually 32-bit reads/writes are always atomic on x86
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But we add LOCK here anyway to force memory barriers
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*/
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#define make_atomic_load_body(S) \
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_asm { \
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_asm mov areg_ ## S, 0 \
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_asm mov reg2_ ## S, areg_ ## S \
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_asm LOCK cmpxchg *a, reg2_ ## S \
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_asm mov ret, areg_ ## S \
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}
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#define make_atomic_store_body(S) \
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_asm { \
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_asm mov reg_ ## S, v \
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_asm xchg *a, reg_ ## S \
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}
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#endif
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#define reg_8 al
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#define reg_16 ax
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#define reg_32 eax
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#define areg_8 al
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#define areg_16 ax
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#define areg_32 eax
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#define reg2_8 bl
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#define reg2_16 bx
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#define reg2_32 ebx
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#else /* cleanup */
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#undef reg_8
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#undef reg_16
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#undef reg_32
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#undef areg_8
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#undef areg_16
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#undef areg_32
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#undef reg2_8
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#undef reg2_16
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#undef reg2_32
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#endif
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