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In order to facilitate the fine-tuning of how `libatomic_i.h' and `host-config.h' headers are used by different atomic functions, we define distinct identifier macros for each file which, in implementing atomic operations, imports these headers. The idea is that different parts of these headers could then be conditionally defined depending on the macros set by the file that `#include'd them. Given how it is possible that some file names are generic enough that using them as-is for macro names (e.g. flag.c -> FLAG) may potentially lead to name clashes with other macros, all file names first have LAT_ prepended to them such that, for example, flag.c is assigned the LAT_FLAG macro. Libatomic/ChangeLog: * cas_n.c (LAT_CAS_N): New. * exch_n.c (LAT_EXCH_N): Likewise. * fadd_n.c (LAT_FADD_N): Likewise. * fand_n.c (LAT_FAND_N): Likewise. * fence.c (LAT_FENCE): Likewise. * fenv.c (LAT_FENV): Likewise. * fior_n.c (LAT_FIOR_N): Likewise. * flag.c (LAT_FLAG): Likewise. * fnand_n.c (LAT_FNAND_N): Likewise. * fop_n.c (LAT_FOP_N): Likewise * fsub_n.c (LAT_FSUB_N): Likewise. * fxor_n.c (LAT_FXOR_N): Likewise. * gcas.c (LAT_GCAS): Likewise. * gexch.c (LAT_GEXCH): Likewise. * glfree.c (LAT_GLFREE): Likewise. * gload.c (LAT_GLOAD): Likewise. * gstore.c (LAT_GSTORE): Likewise. * load_n.c (LAT_LOAD_N): Likewise. * store_n.c (LAT_STORE_N): Likewise. * tas_n.c (LAT_TAS_N): Likewise.
111 lines
3.3 KiB
C
111 lines
3.3 KiB
C
/* Copyright (C) 2012-2024 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Atomic Library (libatomic).
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Libatomic is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#define LAT_GSTORE
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#include "libatomic_i.h"
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/* If we natively support the store, and if we're unconcerned with extra
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barriers (e.g. fully in-order cpu for which barriers are a nop), then
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go ahead and expand the operation inline. */
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#if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
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# define EXACT_INLINE(N) \
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if (C2(HAVE_ATOMIC_LDST_,N)) \
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{ \
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__atomic_store_n (PTR(N,mptr), *PTR(N,vptr), __ATOMIC_SEQ_CST); \
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return; \
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}
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#else
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# define EXACT_INLINE(N)
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#endif
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#define EXACT(N) \
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do { \
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if (!C2(HAVE_INT,N)) break; \
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if ((uintptr_t)mptr & (N - 1)) break; \
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EXACT_INLINE (N); \
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C3(local_,store_,N) (PTR(N,mptr), *PTR(N,vptr), smodel); \
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return; \
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} while (0)
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#define LARGER(N) \
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do { \
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union max_size_u u, v; \
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uintptr_t r, a; \
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if (!C2(HAVE_INT,N)) break; \
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if (!C2(MAYBE_HAVE_ATOMIC_CAS_,N)) break; \
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r = (uintptr_t)mptr & (N - 1); \
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a = (uintptr_t)mptr & -N; \
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if (r + n <= N) \
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{ \
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pre_barrier (smodel); \
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/* This load need not be atomic, as the CAS \
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below will validate it. */ \
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u.C2(i,N) = *PTR(N,a); \
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do { \
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v = u; memcpy (v.b + r, vptr, n); \
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} while (!(C2(HAVE_ATOMIC_CAS_,N) \
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? __atomic_compare_exchange_n (PTR(N,a), \
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&u.C2(i,N), v.C2(i,N), true, \
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__ATOMIC_RELAXED, __ATOMIC_RELAXED) \
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: C3(local_,compare_exchange_,N) (PTR(N,a), \
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&u.C2(i,N), v.C2(i,N), \
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__ATOMIC_RELAXED, __ATOMIC_RELAXED))); \
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post_barrier (smodel); \
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return; \
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} \
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} while (0)
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void
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libat_store (size_t n, void *mptr, void *vptr, int smodel)
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{
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switch (n)
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{
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case 0: return;
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case 1: EXACT(1); goto L4;
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case 2: EXACT(2); goto L4;
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case 4: EXACT(4); goto L8;
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case 8: EXACT(8); goto L16;
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case 16: EXACT(16); break;
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case 3: L4: LARGER(4); /* FALLTHRU */
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case 5 ... 7: L8: LARGER(8); /* FALLTHRU */
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case 9 ... 15: L16: LARGER(16); break;
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}
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pre_seq_barrier (smodel);
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libat_lock_n (mptr, n);
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memcpy (mptr, vptr, n);
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libat_unlock_n (mptr, n);
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post_seq_barrier (smodel);
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}
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EXPORT_ALIAS (store);
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#undef LAT_GSTORE
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