1/* Copyright (c) 2013, Ben Noordhuis <info@bnoordhuis.nl> 2 * 3 * Permission to use, copy, modify, and/or distribute this software for any 4 * purpose with or without fee is hereby granted, provided that the above 5 * copyright notice and this permission notice appear in all copies. 6 * 7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 10 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 12 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 13 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 14 */ 15 16#ifndef UV_ATOMIC_OPS_H_ 17#define UV_ATOMIC_OPS_H_ 18 19#include "internal.h" /* UV_UNUSED */ 20 21#if defined(__SUNPRO_C) || defined(__SUNPRO_CC) 22#include <atomic.h> 23#endif 24 25UV_UNUSED(static int cmpxchgi(int* ptr, int oldval, int newval)); 26UV_UNUSED(static void cpu_relax(void)); 27 28/* Prefer hand-rolled assembly over the gcc builtins because the latter also 29 * issue full memory barriers. 30 */ 31UV_UNUSED(static int cmpxchgi(int* ptr, int oldval, int newval)) { 32#if defined(__i386__) || defined(__x86_64__) 33 int out; 34 __asm__ __volatile__ ("lock; cmpxchg %2, %1;" 35 : "=a" (out), "+m" (*(volatile int*) ptr) 36 : "r" (newval), "0" (oldval) 37 : "memory"); 38 return out; 39#elif defined(__MVS__) 40 /* Use hand-rolled assembly because codegen from builtin __plo_CSST results in 41 * a runtime bug. 42 */ 43 __asm(" cs %0,%2,%1 \n " : "+r"(oldval), "+m"(*ptr) : "r"(newval) :); 44 return oldval; 45#elif defined(__SUNPRO_C) || defined(__SUNPRO_CC) 46 return atomic_cas_uint((uint_t *)ptr, (uint_t)oldval, (uint_t)newval); 47#else 48 return __sync_val_compare_and_swap(ptr, oldval, newval); 49#endif 50} 51 52UV_UNUSED(static void cpu_relax(void)) { 53#if defined(__i386__) || defined(__x86_64__) 54 __asm__ __volatile__ ("rep; nop" ::: "memory"); /* a.k.a. PAUSE */ 55#elif (defined(__arm__) && __ARM_ARCH >= 7) || defined(__aarch64__) 56 __asm__ __volatile__ ("yield" ::: "memory"); 57#elif (defined(__ppc__) || defined(__ppc64__)) && defined(__APPLE__) 58 __asm volatile ("" : : : "memory"); 59#elif !defined(__APPLE__) && (defined(__powerpc64__) || defined(__ppc64__) || defined(__PPC64__)) 60 __asm__ __volatile__ ("or 1,1,1; or 2,2,2" ::: "memory"); 61#endif 62} 63 64#endif /* UV_ATOMIC_OPS_H_ */ 65