| /* Copyright (c) 2013, Ben Noordhuis <info@bnoordhuis.nl> |
| * |
| * Permission to use, copy, modify, and/or distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| #ifndef UV_ATOMIC_OPS_H_ |
| #define UV_ATOMIC_OPS_H_ |
| |
| #include "internal.h" /* UV_UNUSED */ |
| |
| #if defined(__SUNPRO_C) || defined(__SUNPRO_CC) |
| #include <atomic.h> |
| #endif |
| |
| UV_UNUSED(static int cmpxchgi(int* ptr, int oldval, int newval)); |
| UV_UNUSED(static void cpu_relax(void)); |
| |
| /* Prefer hand-rolled assembly over the gcc builtins because the latter also |
| * issue full memory barriers. |
| */ |
| UV_UNUSED(static int cmpxchgi(int* ptr, int oldval, int newval)) { |
| #if defined(__i386__) || defined(__x86_64__) |
| int out; |
| __asm__ __volatile__ ("lock; cmpxchg %2, %1;" |
| : "=a" (out), "+m" (*(volatile int*) ptr) |
| : "r" (newval), "0" (oldval) |
| : "memory"); |
| return out; |
| #elif defined(_AIX) && defined(__ibmxl__) |
| /* FIXME: This is not actually atomic but XLClang 16.1 for AIX |
| does not provide __sync_val_compare_and_swap or an equivalent. |
| Its documentation suggests using C++11 atomics but this is C. */ |
| __compare_and_swap((volatile int*)ptr, &oldval, newval); |
| return oldval; |
| #elif defined(__MVS__) |
| unsigned int op4; |
| if (__plo_CSST(ptr, (unsigned int*) &oldval, newval, |
| (unsigned int*) ptr, *ptr, &op4)) |
| return oldval; |
| else |
| return op4; |
| #elif defined(__SUNPRO_C) || defined(__SUNPRO_CC) |
| return atomic_cas_uint((uint_t *)ptr, (uint_t)oldval, (uint_t)newval); |
| #else |
| return __sync_val_compare_and_swap(ptr, oldval, newval); |
| #endif |
| } |
| |
| UV_UNUSED(static void cpu_relax(void)) { |
| #if defined(__i386__) || defined(__x86_64__) |
| __asm__ __volatile__ ("rep; nop"); /* a.k.a. PAUSE */ |
| #elif (defined(__arm__) && __ARM_ARCH >= 7) || defined(__aarch64__) |
| __asm__ volatile("yield"); |
| #endif |
| } |
| |
| #endif /* UV_ATOMIC_OPS_H_ */ |
