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544 lines
21 KiB
C
544 lines
21 KiB
C
/* Atomic operations. X86 version.
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Copyright (C) 2018-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _X86_ATOMIC_MACHINE_H
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#define _X86_ATOMIC_MACHINE_H 1
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#include <stdint.h>
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#include <tls.h> /* For tcbhead_t. */
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#include <libc-pointer-arith.h> /* For cast_to_integer. */
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#define LOCK_PREFIX "lock;"
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#define USE_ATOMIC_COMPILER_BUILTINS 1
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#ifdef __x86_64__
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# define __HAVE_64B_ATOMICS 1
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# define SP_REG "rsp"
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# define SEG_REG "fs"
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# define BR_CONSTRAINT "q"
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# define IBR_CONSTRAINT "iq"
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#else
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/* Since the Pentium, i386 CPUs have supported 64-bit atomics, but the
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i386 psABI supplement provides only 4-byte alignment for uint64_t
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inside structs, so it is currently not possible to use 64-bit
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atomics on this platform. */
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# define __HAVE_64B_ATOMICS 0
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# define SP_REG "esp"
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# define SEG_REG "gs"
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# define BR_CONSTRAINT "r"
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# define IBR_CONSTRAINT "ir"
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#endif
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#define ATOMIC_EXCHANGE_USES_CAS 0
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#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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__sync_val_compare_and_swap (mem, oldval, newval)
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#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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(! __sync_bool_compare_and_swap (mem, oldval, newval))
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#define __arch_c_compare_and_exchange_val_8_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret; \
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__asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \
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"je 0f\n\t" \
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"lock\n" \
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"0:\tcmpxchgb %b2, %1" \
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: "=a" (ret), "=m" (*mem) \
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: BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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ret; })
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#define __arch_c_compare_and_exchange_val_16_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret; \
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__asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \
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"je 0f\n\t" \
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"lock\n" \
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"0:\tcmpxchgw %w2, %1" \
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: "=a" (ret), "=m" (*mem) \
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: BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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ret; })
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#define __arch_c_compare_and_exchange_val_32_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret; \
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__asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \
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"je 0f\n\t" \
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"lock\n" \
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"0:\tcmpxchgl %2, %1" \
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: "=a" (ret), "=m" (*mem) \
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: BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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ret; })
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#ifdef __x86_64__
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# define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret; \
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__asm __volatile ("cmpl $0, %%fs:%P5\n\t" \
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"je 0f\n\t" \
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"lock\n" \
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"0:\tcmpxchgq %q2, %1" \
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: "=a" (ret), "=m" (*mem) \
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: "q" ((int64_t) cast_to_integer (newval)), \
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"m" (*mem), \
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"0" ((int64_t) cast_to_integer (oldval)), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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ret; })
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# define do_exchange_and_add_val_64_acq(pfx, mem, value) 0
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# define do_add_val_64_acq(pfx, mem, value) do { } while (0)
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#else
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/* XXX We do not really need 64-bit compare-and-exchange. At least
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not in the moment. Using it would mean causing portability
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problems since not many other 32-bit architectures have support for
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such an operation. So don't define any code for now. If it is
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really going to be used the code below can be used on Intel Pentium
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and later, but NOT on i486. */
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# define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret = *(mem); \
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__atomic_link_error (); \
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ret = (newval); \
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ret = (oldval); \
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ret; })
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# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
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({ __typeof (*mem) ret = *(mem); \
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__atomic_link_error (); \
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ret = (newval); \
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ret = (oldval); \
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ret; })
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# define do_exchange_and_add_val_64_acq(pfx, mem, value) \
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({ __typeof (value) __addval = (value); \
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__typeof (*mem) __result; \
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__typeof (mem) __memp = (mem); \
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__typeof (*mem) __tmpval; \
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__result = *__memp; \
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do \
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__tmpval = __result; \
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while ((__result = pfx##_compare_and_exchange_val_64_acq \
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(__memp, __result + __addval, __result)) == __tmpval); \
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__result; })
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# define do_add_val_64_acq(pfx, mem, value) \
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{ \
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__typeof (value) __addval = (value); \
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__typeof (mem) __memp = (mem); \
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__typeof (*mem) __oldval = *__memp; \
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__typeof (*mem) __tmpval; \
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do \
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__tmpval = __oldval; \
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while ((__oldval = pfx##_compare_and_exchange_val_64_acq \
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(__memp, __oldval + __addval, __oldval)) == __tmpval); \
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}
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#endif
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/* Note that we need no lock prefix. */
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#define atomic_exchange_acq(mem, newvalue) \
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({ __typeof (*mem) result; \
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if (sizeof (*mem) == 1) \
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__asm __volatile ("xchgb %b0, %1" \
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: "=q" (result), "=m" (*mem) \
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: "0" (newvalue), "m" (*mem)); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile ("xchgw %w0, %1" \
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: "=r" (result), "=m" (*mem) \
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: "0" (newvalue), "m" (*mem)); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile ("xchgl %0, %1" \
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: "=r" (result), "=m" (*mem) \
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: "0" (newvalue), "m" (*mem)); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile ("xchgq %q0, %1" \
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: "=r" (result), "=m" (*mem) \
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: "0" ((int64_t) cast_to_integer (newvalue)), \
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"m" (*mem)); \
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else \
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{ \
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result = 0; \
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__atomic_link_error (); \
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} \
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result; })
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#define __arch_exchange_and_add_body(lock, pfx, mem, value) \
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({ __typeof (*mem) __result; \
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__typeof (value) __addval = (value); \
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if (sizeof (*mem) == 1) \
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__asm __volatile (lock "xaddb %b0, %1" \
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: "=q" (__result), "=m" (*mem) \
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: "0" (__addval), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (lock "xaddw %w0, %1" \
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: "=r" (__result), "=m" (*mem) \
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: "0" (__addval), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (lock "xaddl %0, %1" \
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: "=r" (__result), "=m" (*mem) \
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: "0" (__addval), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (lock "xaddq %q0, %1" \
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: "=r" (__result), "=m" (*mem) \
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: "0" ((int64_t) cast_to_integer (__addval)), \
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"m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else \
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__result = do_exchange_and_add_val_64_acq (pfx, (mem), __addval); \
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__result; })
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#define atomic_exchange_and_add(mem, value) \
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__sync_fetch_and_add (mem, value)
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#define __arch_exchange_and_add_cprefix \
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"cmpl $0, %%" SEG_REG ":%P4\n\tje 0f\n\tlock\n0:\t"
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#define catomic_exchange_and_add(mem, value) \
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__arch_exchange_and_add_body (__arch_exchange_and_add_cprefix, __arch_c, \
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mem, value)
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#define __arch_add_body(lock, pfx, apfx, mem, value) \
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do { \
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if (__builtin_constant_p (value) && (value) == 1) \
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pfx##_increment (mem); \
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else if (__builtin_constant_p (value) && (value) == -1) \
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pfx##_decrement (mem); \
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else if (sizeof (*mem) == 1) \
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__asm __volatile (lock "addb %b1, %0" \
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: "=m" (*mem) \
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: IBR_CONSTRAINT (value), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (lock "addw %w1, %0" \
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: "=m" (*mem) \
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: "ir" (value), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (lock "addl %1, %0" \
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: "=m" (*mem) \
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: "ir" (value), "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (lock "addq %q1, %0" \
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: "=m" (*mem) \
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: "ir" ((int64_t) cast_to_integer (value)), \
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"m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else \
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do_add_val_64_acq (apfx, (mem), (value)); \
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} while (0)
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# define atomic_add(mem, value) \
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__arch_add_body (LOCK_PREFIX, atomic, __arch, mem, value)
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#define __arch_add_cprefix \
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"cmpl $0, %%" SEG_REG ":%P3\n\tje 0f\n\tlock\n0:\t"
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#define catomic_add(mem, value) \
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__arch_add_body (__arch_add_cprefix, atomic, __arch_c, mem, value)
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#define atomic_add_negative(mem, value) \
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({ unsigned char __result; \
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if (sizeof (*mem) == 1) \
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__asm __volatile (LOCK_PREFIX "addb %b2, %0; sets %1" \
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: "=m" (*mem), "=qm" (__result) \
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: IBR_CONSTRAINT (value), "m" (*mem)); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (LOCK_PREFIX "addw %w2, %0; sets %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" (value), "m" (*mem)); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (LOCK_PREFIX "addl %2, %0; sets %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" (value), "m" (*mem)); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (LOCK_PREFIX "addq %q2, %0; sets %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" ((int64_t) cast_to_integer (value)), \
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"m" (*mem)); \
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else \
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__atomic_link_error (); \
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__result; })
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#define atomic_add_zero(mem, value) \
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({ unsigned char __result; \
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if (sizeof (*mem) == 1) \
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__asm __volatile (LOCK_PREFIX "addb %b2, %0; setz %1" \
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: "=m" (*mem), "=qm" (__result) \
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: IBR_CONSTRAINT (value), "m" (*mem)); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (LOCK_PREFIX "addw %w2, %0; setz %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" (value), "m" (*mem)); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (LOCK_PREFIX "addl %2, %0; setz %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" (value), "m" (*mem)); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (LOCK_PREFIX "addq %q2, %0; setz %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "ir" ((int64_t) cast_to_integer (value)), \
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"m" (*mem)); \
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else \
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__atomic_link_error (); \
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__result; })
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#define __arch_increment_body(lock, pfx, mem) \
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do { \
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if (sizeof (*mem) == 1) \
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__asm __volatile (lock "incb %b0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (lock "incw %w0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (lock "incl %0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (lock "incq %q0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else \
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do_add_val_64_acq (pfx, mem, 1); \
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} while (0)
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#define atomic_increment(mem) __arch_increment_body (LOCK_PREFIX, __arch, mem)
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#define __arch_increment_cprefix \
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"cmpl $0, %%" SEG_REG ":%P2\n\tje 0f\n\tlock\n0:\t"
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#define catomic_increment(mem) \
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__arch_increment_body (__arch_increment_cprefix, __arch_c, mem)
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#define atomic_increment_and_test(mem) \
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({ unsigned char __result; \
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if (sizeof (*mem) == 1) \
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__asm __volatile (LOCK_PREFIX "incb %b0; sete %b1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (LOCK_PREFIX "incw %w0; sete %w1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (LOCK_PREFIX "incl %0; sete %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (LOCK_PREFIX "incq %q0; sete %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else \
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__atomic_link_error (); \
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__result; })
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#define __arch_decrement_body(lock, pfx, mem) \
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do { \
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if (sizeof (*mem) == 1) \
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__asm __volatile (lock "decb %b0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (lock "decw %w0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (lock "decl %0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else if (__HAVE_64B_ATOMICS) \
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__asm __volatile (lock "decq %q0" \
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: "=m" (*mem) \
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: "m" (*mem), \
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"i" (offsetof (tcbhead_t, multiple_threads))); \
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else \
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do_add_val_64_acq (pfx, mem, -1); \
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} while (0)
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#define atomic_decrement(mem) __arch_decrement_body (LOCK_PREFIX, __arch, mem)
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#define __arch_decrement_cprefix \
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"cmpl $0, %%" SEG_REG ":%P2\n\tje 0f\n\tlock\n0:\t"
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#define catomic_decrement(mem) \
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__arch_decrement_body (__arch_decrement_cprefix, __arch_c, mem)
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#define atomic_decrement_and_test(mem) \
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({ unsigned char __result; \
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if (sizeof (*mem) == 1) \
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__asm __volatile (LOCK_PREFIX "decb %b0; sete %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else if (sizeof (*mem) == 2) \
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__asm __volatile (LOCK_PREFIX "decw %w0; sete %1" \
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: "=m" (*mem), "=qm" (__result) \
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: "m" (*mem)); \
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else if (sizeof (*mem) == 4) \
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__asm __volatile (LOCK_PREFIX "decl %0; sete %1" \
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: "=m" (*mem), "=qm" (__result) \
|
|
: "m" (*mem)); \
|
|
else \
|
|
__asm __volatile (LOCK_PREFIX "decq %q0; sete %1" \
|
|
: "=m" (*mem), "=qm" (__result) \
|
|
: "m" (*mem)); \
|
|
__result; })
|
|
|
|
|
|
#define atomic_bit_set(mem, bit) \
|
|
do { \
|
|
if (sizeof (*mem) == 1) \
|
|
__asm __volatile (LOCK_PREFIX "orb %b2, %0" \
|
|
: "=m" (*mem) \
|
|
: "m" (*mem), IBR_CONSTRAINT (1L << (bit))); \
|
|
else if (sizeof (*mem) == 2) \
|
|
__asm __volatile (LOCK_PREFIX "orw %w2, %0" \
|
|
: "=m" (*mem) \
|
|
: "m" (*mem), "ir" (1L << (bit))); \
|
|
else if (sizeof (*mem) == 4) \
|
|
__asm __volatile (LOCK_PREFIX "orl %2, %0" \
|
|
: "=m" (*mem) \
|
|
: "m" (*mem), "ir" (1L << (bit))); \
|
|
else if (__builtin_constant_p (bit) && (bit) < 32) \
|
|
__asm __volatile (LOCK_PREFIX "orq %2, %0" \
|
|
: "=m" (*mem) \
|
|
: "m" (*mem), "i" (1L << (bit))); \
|
|
else if (__HAVE_64B_ATOMICS) \
|
|
__asm __volatile (LOCK_PREFIX "orq %q2, %0" \
|
|
: "=m" (*mem) \
|
|
: "m" (*mem), "r" (1UL << (bit))); \
|
|
else \
|
|
__atomic_link_error (); \
|
|
} while (0)
|
|
|
|
|
|
#define atomic_bit_test_set(mem, bit) \
|
|
({ unsigned char __result; \
|
|
if (sizeof (*mem) == 1) \
|
|
__asm __volatile (LOCK_PREFIX "btsb %3, %1; setc %0" \
|
|
: "=q" (__result), "=m" (*mem) \
|
|
: "m" (*mem), IBR_CONSTRAINT (bit)); \
|
|
else if (sizeof (*mem) == 2) \
|
|
__asm __volatile (LOCK_PREFIX "btsw %3, %1; setc %0" \
|
|
: "=q" (__result), "=m" (*mem) \
|
|
: "m" (*mem), "ir" (bit)); \
|
|
else if (sizeof (*mem) == 4) \
|
|
__asm __volatile (LOCK_PREFIX "btsl %3, %1; setc %0" \
|
|
: "=q" (__result), "=m" (*mem) \
|
|
: "m" (*mem), "ir" (bit)); \
|
|
else if (__HAVE_64B_ATOMICS) \
|
|
__asm __volatile (LOCK_PREFIX "btsq %3, %1; setc %0" \
|
|
: "=q" (__result), "=m" (*mem) \
|
|
: "m" (*mem), "ir" (bit)); \
|
|
else \
|
|
__atomic_link_error (); \
|
|
__result; })
|
|
|
|
|
|
#define __arch_and_body(lock, mem, mask) \
|
|
do { \
|
|
if (sizeof (*mem) == 1) \
|
|
__asm __volatile (lock "andb %b1, %0" \
|
|
: "=m" (*mem) \
|
|
: IBR_CONSTRAINT (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (sizeof (*mem) == 2) \
|
|
__asm __volatile (lock "andw %w1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (sizeof (*mem) == 4) \
|
|
__asm __volatile (lock "andl %1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (__HAVE_64B_ATOMICS) \
|
|
__asm __volatile (lock "andq %q1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else \
|
|
__atomic_link_error (); \
|
|
} while (0)
|
|
|
|
#define __arch_cprefix \
|
|
"cmpl $0, %%" SEG_REG ":%P3\n\tje 0f\n\tlock\n0:\t"
|
|
|
|
#define atomic_and(mem, mask) __arch_and_body (LOCK_PREFIX, mem, mask)
|
|
|
|
#define catomic_and(mem, mask) __arch_and_body (__arch_cprefix, mem, mask)
|
|
|
|
|
|
#define __arch_or_body(lock, mem, mask) \
|
|
do { \
|
|
if (sizeof (*mem) == 1) \
|
|
__asm __volatile (lock "orb %b1, %0" \
|
|
: "=m" (*mem) \
|
|
: IBR_CONSTRAINT (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (sizeof (*mem) == 2) \
|
|
__asm __volatile (lock "orw %w1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (sizeof (*mem) == 4) \
|
|
__asm __volatile (lock "orl %1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else if (__HAVE_64B_ATOMICS) \
|
|
__asm __volatile (lock "orq %q1, %0" \
|
|
: "=m" (*mem) \
|
|
: "ir" (mask), "m" (*mem), \
|
|
"i" (offsetof (tcbhead_t, multiple_threads))); \
|
|
else \
|
|
__atomic_link_error (); \
|
|
} while (0)
|
|
|
|
#define atomic_or(mem, mask) __arch_or_body (LOCK_PREFIX, mem, mask)
|
|
|
|
#define catomic_or(mem, mask) __arch_or_body (__arch_cprefix, mem, mask)
|
|
|
|
/* We don't use mfence because it is supposedly slower due to having to
|
|
provide stronger guarantees (e.g., regarding self-modifying code). */
|
|
#define atomic_full_barrier() \
|
|
__asm __volatile (LOCK_PREFIX "orl $0, (%%" SP_REG ")" ::: "memory")
|
|
#define atomic_read_barrier() __asm ("" ::: "memory")
|
|
#define atomic_write_barrier() __asm ("" ::: "memory")
|
|
|
|
#define atomic_spin_nop() __asm ("pause")
|
|
|
|
#endif /* atomic-machine.h */
|