diff options
Diffstat (limited to 'sysdeps/x86/atomic-machine.h')
| -rw-r--r-- | sysdeps/x86/atomic-machine.h | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/sysdeps/x86/atomic-machine.h b/sysdeps/x86/atomic-machine.h new file mode 100644 index 0000000000..ea9a46a802 --- /dev/null +++ b/sysdeps/x86/atomic-machine.h @@ -0,0 +1,571 @@ +/* Atomic operations. X86 version. + Copyright (C) 2018-2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _X86_ATOMIC_MACHINE_H +#define _X86_ATOMIC_MACHINE_H 1 + +#include <stdint.h> +#include <tls.h> /* For tcbhead_t. */ +#include <libc-pointer-arith.h> /* For cast_to_integer. */ + +typedef int8_t atomic8_t; +typedef uint8_t uatomic8_t; +typedef int_fast8_t atomic_fast8_t; +typedef uint_fast8_t uatomic_fast8_t; + +typedef int16_t atomic16_t; +typedef uint16_t uatomic16_t; +typedef int_fast16_t atomic_fast16_t; +typedef uint_fast16_t uatomic_fast16_t; + +typedef int32_t atomic32_t; +typedef uint32_t uatomic32_t; +typedef int_fast32_t atomic_fast32_t; +typedef uint_fast32_t uatomic_fast32_t; + +typedef int64_t atomic64_t; +typedef uint64_t uatomic64_t; +typedef int_fast64_t atomic_fast64_t; +typedef uint_fast64_t uatomic_fast64_t; + +typedef intptr_t atomicptr_t; +typedef uintptr_t uatomicptr_t; +typedef intmax_t atomic_max_t; +typedef uintmax_t uatomic_max_t; + + +#ifndef LOCK_PREFIX +# ifdef UP +# define LOCK_PREFIX /* nothing */ +# else +# define LOCK_PREFIX "lock;" +# endif +#endif + +#define USE_ATOMIC_COMPILER_BUILTINS 1 + +#ifdef __x86_64__ +# define __HAVE_64B_ATOMICS 1 +# define SP_REG "rsp" +# define SEG_REG "fs" +# define BR_CONSTRAINT "q" +# define IBR_CONSTRAINT "iq" +#else +# define __HAVE_64B_ATOMICS 0 +# define SP_REG "esp" +# define SEG_REG "gs" +# define BR_CONSTRAINT "r" +# define IBR_CONSTRAINT "ir" +#endif +#define ATOMIC_EXCHANGE_USES_CAS 0 + +#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \ + __sync_val_compare_and_swap (mem, oldval, newval) +#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \ + (! __sync_bool_compare_and_swap (mem, oldval, newval)) + + +#define __arch_c_compare_and_exchange_val_8_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret; \ + __asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \ + "je 0f\n\t" \ + "lock\n" \ + "0:\tcmpxchgb %b2, %1" \ + : "=a" (ret), "=m" (*mem) \ + : BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + ret; }) + +#define __arch_c_compare_and_exchange_val_16_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret; \ + __asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \ + "je 0f\n\t" \ + "lock\n" \ + "0:\tcmpxchgw %w2, %1" \ + : "=a" (ret), "=m" (*mem) \ + : BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + ret; }) + +#define __arch_c_compare_and_exchange_val_32_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret; \ + __asm __volatile ("cmpl $0, %%" SEG_REG ":%P5\n\t" \ + "je 0f\n\t" \ + "lock\n" \ + "0:\tcmpxchgl %2, %1" \ + : "=a" (ret), "=m" (*mem) \ + : BR_CONSTRAINT (newval), "m" (*mem), "0" (oldval), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + ret; }) + +#ifdef __x86_64__ +# define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret; \ + __asm __volatile ("cmpl $0, %%fs:%P5\n\t" \ + "je 0f\n\t" \ + "lock\n" \ + "0:\tcmpxchgq %q2, %1" \ + : "=a" (ret), "=m" (*mem) \ + : "q" ((atomic64_t) cast_to_integer (newval)), \ + "m" (*mem), \ + "0" ((atomic64_t) cast_to_integer (oldval)), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + ret; }) +# define do_exchange_and_add_val_64_acq(pfx, mem, value) 0 +# define do_add_val_64_acq(pfx, mem, value) do { } while (0) +#else +/* XXX We do not really need 64-bit compare-and-exchange. At least + not in the moment. Using it would mean causing portability + problems since not many other 32-bit architectures have support for + such an operation. So don't define any code for now. If it is + really going to be used the code below can be used on Intel Pentium + and later, but NOT on i486. */ +# define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret = *(mem); \ + __atomic_link_error (); \ + ret = (newval); \ + ret = (oldval); \ + ret; }) + +# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \ + ({ __typeof (*mem) ret = *(mem); \ + __atomic_link_error (); \ + ret = (newval); \ + ret = (oldval); \ + ret; }) + +# define do_exchange_and_add_val_64_acq(pfx, mem, value) \ + ({ __typeof (value) __addval = (value); \ + __typeof (*mem) __result; \ + __typeof (mem) __memp = (mem); \ + __typeof (*mem) __tmpval; \ + __result = *__memp; \ + do \ + __tmpval = __result; \ + while ((__result = pfx##_compare_and_exchange_val_64_acq \ + (__memp, __result + __addval, __result)) == __tmpval); \ + __result; }) + +# define do_add_val_64_acq(pfx, mem, value) \ + { \ + __typeof (value) __addval = (value); \ + __typeof (mem) __memp = (mem); \ + __typeof (*mem) __oldval = *__memp; \ + __typeof (*mem) __tmpval; \ + do \ + __tmpval = __oldval; \ + while ((__oldval = pfx##_compare_and_exchange_val_64_acq \ + (__memp, __oldval + __addval, __oldval)) == __tmpval); \ + } +#endif + + +/* Note that we need no lock prefix. */ +#define atomic_exchange_acq(mem, newvalue) \ + ({ __typeof (*mem) result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile ("xchgb %b0, %1" \ + : "=q" (result), "=m" (*mem) \ + : "0" (newvalue), "m" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile ("xchgw %w0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "m" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile ("xchgl %0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" (newvalue), "m" (*mem)); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile ("xchgq %q0, %1" \ + : "=r" (result), "=m" (*mem) \ + : "0" ((atomic64_t) cast_to_integer (newvalue)), \ + "m" (*mem)); \ + else \ + { \ + result = 0; \ + __atomic_link_error (); \ + } \ + result; }) + + +#define __arch_exchange_and_add_body(lock, pfx, mem, value) \ + ({ __typeof (*mem) __result; \ + __typeof (value) __addval = (value); \ + if (sizeof (*mem) == 1) \ + __asm __volatile (lock "xaddb %b0, %1" \ + : "=q" (__result), "=m" (*mem) \ + : "0" (__addval), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "xaddw %w0, %1" \ + : "=r" (__result), "=m" (*mem) \ + : "0" (__addval), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "xaddl %0, %1" \ + : "=r" (__result), "=m" (*mem) \ + : "0" (__addval), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "xaddq %q0, %1" \ + : "=r" (__result), "=m" (*mem) \ + : "0" ((atomic64_t) cast_to_integer (__addval)), \ + "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + __result = do_exchange_and_add_val_64_acq (pfx, (mem), __addval); \ + __result; }) + +#define atomic_exchange_and_add(mem, value) \ + __sync_fetch_and_add (mem, value) + +#define __arch_exchange_and_add_cprefix \ + "cmpl $0, %%" SEG_REG ":%P4\n\tje 0f\n\tlock\n0:\t" + +#define catomic_exchange_and_add(mem, value) \ + __arch_exchange_and_add_body (__arch_exchange_and_add_cprefix, __arch_c, \ + mem, value) + + +#define __arch_add_body(lock, pfx, apfx, mem, value) \ + do { \ + if (__builtin_constant_p (value) && (value) == 1) \ + pfx##_increment (mem); \ + else if (__builtin_constant_p (value) && (value) == -1) \ + pfx##_decrement (mem); \ + else if (sizeof (*mem) == 1) \ + __asm __volatile (lock "addb %b1, %0" \ + : "=m" (*mem) \ + : IBR_CONSTRAINT (value), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "addw %w1, %0" \ + : "=m" (*mem) \ + : "ir" (value), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "addl %1, %0" \ + : "=m" (*mem) \ + : "ir" (value), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "addq %q1, %0" \ + : "=m" (*mem) \ + : "ir" ((atomic64_t) cast_to_integer (value)), \ + "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + do_add_val_64_acq (apfx, (mem), (value)); \ + } while (0) + +# define atomic_add(mem, value) \ + __arch_add_body (LOCK_PREFIX, atomic, __arch, mem, value) + +#define __arch_add_cprefix \ + "cmpl $0, %%" SEG_REG ":%P3\n\tje 0f\n\tlock\n0:\t" + +#define catomic_add(mem, value) \ + __arch_add_body (__arch_add_cprefix, atomic, __arch_c, mem, value) + + +#define atomic_add_negative(mem, value) \ + ({ unsigned char __result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "addb %b2, %0; sets %1" \ + : "=m" (*mem), "=qm" (__result) \ + : IBR_CONSTRAINT (value), "m" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "addw %w2, %0; sets %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" (value), "m" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "addl %2, %0; sets %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" (value), "m" (*mem)); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (LOCK_PREFIX "addq %q2, %0; sets %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" ((atomic64_t) cast_to_integer (value)), \ + "m" (*mem)); \ + else \ + __atomic_link_error (); \ + __result; }) + + +#define atomic_add_zero(mem, value) \ + ({ unsigned char __result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "addb %b2, %0; setz %1" \ + : "=m" (*mem), "=qm" (__result) \ + : IBR_CONSTRAINT (value), "m" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "addw %w2, %0; setz %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" (value), "m" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "addl %2, %0; setz %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" (value), "m" (*mem)); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (LOCK_PREFIX "addq %q2, %0; setz %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "ir" ((atomic64_t) cast_to_integer (value)), \ + "m" (*mem)); \ + else \ + __atomic_link_error (); \ + __result; }) + + +#define __arch_increment_body(lock, pfx, mem) \ + do { \ + if (sizeof (*mem) == 1) \ + __asm __volatile (lock "incb %b0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "incw %w0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "incl %0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "incq %q0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + do_add_val_64_acq (pfx, mem, 1); \ + } while (0) + +#define atomic_increment(mem) __arch_increment_body (LOCK_PREFIX, __arch, mem) + +#define __arch_increment_cprefix \ + "cmpl $0, %%" SEG_REG ":%P2\n\tje 0f\n\tlock\n0:\t" + +#define catomic_increment(mem) \ + __arch_increment_body (__arch_increment_cprefix, __arch_c, mem) + + +#define atomic_increment_and_test(mem) \ + ({ unsigned char __result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "incb %b0; sete %b1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "incw %w0; sete %w1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "incl %0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (LOCK_PREFIX "incq %q0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else \ + __atomic_link_error (); \ + __result; }) + + +#define __arch_decrement_body(lock, pfx, mem) \ + do { \ + if (sizeof (*mem) == 1) \ + __asm __volatile (lock "decb %b0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "decw %w0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "decl %0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "decq %q0" \ + : "=m" (*mem) \ + : "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + do_add_val_64_acq (pfx, mem, -1); \ + } while (0) + +#define atomic_decrement(mem) __arch_decrement_body (LOCK_PREFIX, __arch, mem) + +#define __arch_decrement_cprefix \ + "cmpl $0, %%" SEG_REG ":%P2\n\tje 0f\n\tlock\n0:\t" + +#define catomic_decrement(mem) \ + __arch_decrement_body (__arch_decrement_cprefix, __arch_c, mem) + + +#define atomic_decrement_and_test(mem) \ + ({ unsigned char __result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "decb %b0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "decw %w0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "decl %0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + else \ + __asm __volatile (LOCK_PREFIX "decq %q0; sete %1" \ + : "=m" (*mem), "=qm" (__result) \ + : "m" (*mem)); \ + __result; }) + + +#define atomic_bit_set(mem, bit) \ + do { \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "orb %b2, %0" \ + : "=m" (*mem) \ + : "m" (*mem), IBR_CONSTRAINT (1L << (bit))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "orw %w2, %0" \ + : "=m" (*mem) \ + : "m" (*mem), "ir" (1L << (bit))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "orl %2, %0" \ + : "=m" (*mem) \ + : "m" (*mem), "ir" (1L << (bit))); \ + else if (__builtin_constant_p (bit) && (bit) < 32) \ + __asm __volatile (LOCK_PREFIX "orq %2, %0" \ + : "=m" (*mem) \ + : "m" (*mem), "i" (1L << (bit))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (LOCK_PREFIX "orq %q2, %0" \ + : "=m" (*mem) \ + : "m" (*mem), "r" (1UL << (bit))); \ + else \ + __atomic_link_error (); \ + } while (0) + + +#define atomic_bit_test_set(mem, bit) \ + ({ unsigned char __result; \ + if (sizeof (*mem) == 1) \ + __asm __volatile (LOCK_PREFIX "btsb %3, %1; setc %0" \ + : "=q" (__result), "=m" (*mem) \ + : "m" (*mem), IBR_CONSTRAINT (bit)); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (LOCK_PREFIX "btsw %3, %1; setc %0" \ + : "=q" (__result), "=m" (*mem) \ + : "m" (*mem), "ir" (bit)); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (LOCK_PREFIX "btsl %3, %1; setc %0" \ + : "=q" (__result), "=m" (*mem) \ + : "m" (*mem), "ir" (bit)); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (LOCK_PREFIX "btsq %3, %1; setc %0" \ + : "=q" (__result), "=m" (*mem) \ + : "m" (*mem), "ir" (bit)); \ + else \ + __atomic_link_error (); \ + __result; }) + + +#define __arch_and_body(lock, mem, mask) \ + do { \ + if (sizeof (*mem) == 1) \ + __asm __volatile (lock "andb %b1, %0" \ + : "=m" (*mem) \ + : IBR_CONSTRAINT (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "andw %w1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "andl %1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "andq %q1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + __atomic_link_error (); \ + } while (0) + +#define __arch_cprefix \ + "cmpl $0, %%" SEG_REG ":%P3\n\tje 0f\n\tlock\n0:\t" + +#define atomic_and(mem, mask) __arch_and_body (LOCK_PREFIX, mem, mask) + +#define catomic_and(mem, mask) __arch_and_body (__arch_cprefix, mem, mask) + + +#define __arch_or_body(lock, mem, mask) \ + do { \ + if (sizeof (*mem) == 1) \ + __asm __volatile (lock "orb %b1, %0" \ + : "=m" (*mem) \ + : IBR_CONSTRAINT (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 2) \ + __asm __volatile (lock "orw %w1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (sizeof (*mem) == 4) \ + __asm __volatile (lock "orl %1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else if (__HAVE_64B_ATOMICS) \ + __asm __volatile (lock "orq %q1, %0" \ + : "=m" (*mem) \ + : "ir" (mask), "m" (*mem), \ + "i" (offsetof (tcbhead_t, multiple_threads))); \ + else \ + __atomic_link_error (); \ + } while (0) + +#define atomic_or(mem, mask) __arch_or_body (LOCK_PREFIX, mem, mask) + +#define catomic_or(mem, mask) __arch_or_body (__arch_cprefix, mem, mask) + +/* We don't use mfence because it is supposedly slower due to having to + provide stronger guarantees (e.g., regarding self-modifying code). */ +#define atomic_full_barrier() \ + __asm __volatile (LOCK_PREFIX "orl $0, (%%" SP_REG ")" ::: "memory") +#define atomic_read_barrier() __asm ("" ::: "memory") +#define atomic_write_barrier() __asm ("" ::: "memory") + +#define atomic_spin_nop() __asm ("pause") + +#endif /* atomic-machine.h */ |