git://gcc.gnu.org / gcc.git / blame
| Commit | Line | Data |
|---|---|---|
| 3e6a2e37 | 1 | /* Copyright (C) 2012-2014 Free Software Foundation, Inc. |
| 48310492 RH |
2 | Contributed by Richard Henderson <rth@redhat.com>. |
| 3 | ||
| 4 | This file is part of the GNU Atomic Library (libatomic). | |
| 5 | ||
| 6 | Libatomic is free software; you can redistribute it and/or modify it | |
| 7 | under the terms of the GNU General Public License as published by | |
| 8 | the Free Software Foundation; either version 3 of the License, or | |
| 9 | (at your option) any later version. | |
| 10 | ||
| 11 | Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
| 13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 14 | more details. | |
| 15 | ||
| 16 | Under Section 7 of GPL version 3, you are granted additional | |
| 17 | permissions described in the GCC Runtime Library Exception, version | |
| 18 | 3.1, as published by the Free Software Foundation. | |
| 19 | ||
| 20 | You should have received a copy of the GNU General Public License and | |
| 21 | a copy of the GCC Runtime Library Exception along with this program; | |
| 22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
| 23 | <http://www.gnu.org/licenses/>. */ | |
| 24 | ||
| 25 | #include "libatomic_i.h" | |
| 26 | ||
| 27 | ||
| 28 | /* If we natively support the load, and if we're unconcerned with extra | |
| 29 | barriers (e.g. fully in-order cpu for which barriers are a nop), then | |
| 30 | go ahead and expand the operation inline. */ | |
| 31 | #if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__) | |
| 32 | # define EXACT_INLINE(N, DEST, SRC, DONE) \ | |
| 33 | if (C2(HAVE_ATOMIC_LDST_,N)) \ | |
| 34 | { \ | |
| 94f3ccc8 | 35 | DEST = __atomic_load_n (SRC, __ATOMIC_SEQ_CST); \ |
| 48310492 RH |
36 | DONE; \ |
| 37 | } | |
| 38 | #else | |
| 39 | # define EXACT_INLINE(N, DEST, SRC, DONE) | |
| 40 | #endif | |
| 41 | ||
| 42 | ||
| 43 | #define EXACT_(N, DEST, SRC, DONE) \ | |
| 44 | do { \ | |
| 45 | EXACT_INLINE (N, DEST, SRC, DONE); \ | |
| 46 | DEST = C3(local_,load_,N) (SRC, smodel); \ | |
| 47 | DONE; \ | |
| 48 | } while (0) | |
| 49 | ||
| 50 | #define EXACT(N) \ | |
| 51 | do { \ | |
| 52 | if (!C2(HAVE_INT,N)) break; \ | |
| 53 | if ((uintptr_t)mptr & (N - 1)) break; \ | |
| 54 | EXACT_(N, *PTR(N,rptr), PTR(N,mptr), return); \ | |
| 55 | } while (0) | |
| 56 | ||
| 57 | #define LARGER(N) \ | |
| 58 | do { \ | |
| 59 | if (!C2(HAVE_INT,N)) break; \ | |
| 60 | r = (uintptr_t)mptr & (N - 1); \ | |
| 61 | a = (uintptr_t)mptr & -N; \ | |
| 62 | if (r + n <= N) \ | |
| 63 | EXACT_ (N, u.C2(i,N), PTR(N,a), goto Lfinish); \ | |
| 64 | } while (0) | |
| 65 | ||
| 66 | ||
| 67 | void | |
| 68 | libat_load (size_t n, void *mptr, void *rptr, int smodel) | |
| 69 | { | |
| 70 | union max_size_u u; | |
| 71 | uintptr_t r, a; | |
| 72 | ||
| 73 | switch (n) | |
| 74 | { | |
| 75 | case 0: return; | |
| 76 | case 1: EXACT(1); goto L4; | |
| 77 | case 2: EXACT(2); goto L4; | |
| 78 | case 4: EXACT(4); goto L8; | |
| 79 | case 8: EXACT(8); goto L16; | |
| 80 | case 16: EXACT(16); break; | |
| 81 | ||
| 82 | case 3: L4: LARGER(4); /* FALLTHRU */ | |
| 83 | case 5 ... 7: L8: LARGER(8); /* FALLTHRU */ | |
| 84 | case 9 ... 15: L16: LARGER(16); break; | |
| 85 | ||
| 86 | Lfinish: | |
| 87 | memcpy (rptr, u.b + r, n); | |
| 88 | return; | |
| 89 | } | |
| 90 | ||
| 91 | pre_seq_barrier (smodel); | |
| 92 | libat_lock_n (mptr, n); | |
| 93 | ||
| 94 | memcpy (rptr, mptr, n); | |
| 95 | ||
| 96 | libat_unlock_n (mptr, n); | |
| 97 | post_seq_barrier (smodel); | |
| 98 | } | |
| 99 | ||
| 100 | EXPORT_ALIAS (load); |