gcc/libatomic/gstore.c
Victor Do Nascimento 6edf6fe75b Libatomic: Define per-file identifier macros
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.
2024-06-12 10:23:38 +01:00

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C

/* Copyright (C) 2012-2024 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Atomic Library (libatomic).
Libatomic 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 3 of the License, or
(at your option) any later version.
Libatomic 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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#define LAT_GSTORE
#include "libatomic_i.h"
/* If we natively support the store, and if we're unconcerned with extra
barriers (e.g. fully in-order cpu for which barriers are a nop), then
go ahead and expand the operation inline. */
#if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
# define EXACT_INLINE(N) \
if (C2(HAVE_ATOMIC_LDST_,N)) \
{ \
__atomic_store_n (PTR(N,mptr), *PTR(N,vptr), __ATOMIC_SEQ_CST); \
return; \
}
#else
# define EXACT_INLINE(N)
#endif
#define EXACT(N) \
do { \
if (!C2(HAVE_INT,N)) break; \
if ((uintptr_t)mptr & (N - 1)) break; \
EXACT_INLINE (N); \
C3(local_,store_,N) (PTR(N,mptr), *PTR(N,vptr), smodel); \
return; \
} while (0)
#define LARGER(N) \
do { \
union max_size_u u, v; \
uintptr_t r, a; \
if (!C2(HAVE_INT,N)) break; \
if (!C2(MAYBE_HAVE_ATOMIC_CAS_,N)) break; \
r = (uintptr_t)mptr & (N - 1); \
a = (uintptr_t)mptr & -N; \
if (r + n <= N) \
{ \
pre_barrier (smodel); \
/* This load need not be atomic, as the CAS \
below will validate it. */ \
u.C2(i,N) = *PTR(N,a); \
do { \
v = u; memcpy (v.b + r, vptr, n); \
} while (!(C2(HAVE_ATOMIC_CAS_,N) \
? __atomic_compare_exchange_n (PTR(N,a), \
&u.C2(i,N), v.C2(i,N), true, \
__ATOMIC_RELAXED, __ATOMIC_RELAXED) \
: C3(local_,compare_exchange_,N) (PTR(N,a), \
&u.C2(i,N), v.C2(i,N), \
__ATOMIC_RELAXED, __ATOMIC_RELAXED))); \
post_barrier (smodel); \
return; \
} \
} while (0)
void
libat_store (size_t n, void *mptr, void *vptr, int smodel)
{
switch (n)
{
case 0: return;
case 1: EXACT(1); goto L4;
case 2: EXACT(2); goto L4;
case 4: EXACT(4); goto L8;
case 8: EXACT(8); goto L16;
case 16: EXACT(16); break;
case 3: L4: LARGER(4); /* FALLTHRU */
case 5 ... 7: L8: LARGER(8); /* FALLTHRU */
case 9 ... 15: L16: LARGER(16); break;
}
pre_seq_barrier (smodel);
libat_lock_n (mptr, n);
memcpy (mptr, vptr, n);
libat_unlock_n (mptr, n);
post_seq_barrier (smodel);
}
EXPORT_ALIAS (store);
#undef LAT_GSTORE