Move i486/bits/atomic.h to bits/atomic.h

Since glibc doesn't support i386 any more, we can move i486/bits/atomic.h
to bits/atomic.h.

	* sysdeps/i386/i486/bits/atomic.h: Moved to ...
	* sysdeps/i386/bits/atomic.h: Here.

1 files changed, 544 insertions, 0 deletions

diff --git a/sysdeps/i386/bits/atomic.h b/sysdeps/i386/bits/atomic.h
new file mode 100644
index 0000000000..59f3d34871
--- /dev/null
+++ b/sysdeps/i386/bits/atomic.h
@@ -0,0 +1,544 @@
+/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdint.h>
+#include <tls.h>	/* For tcbhead_t.  */
+
+
+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 __HAVE_64B_ATOMICS 0
+#define USE_ATOMIC_COMPILER_BUILTINS 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, %%gs:%P5\n\t"                                \
+                       "je 0f\n\t"                                            \
+                       "lock\n"                                               \
+                       "0:\tcmpxchgb %b2, %1"				      \
+		       : "=a" (ret), "=m" (*mem)			      \
+		       : "q" (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, %%gs:%P5\n\t"                                \
+                       "je 0f\n\t"                                            \
+                       "lock\n"                                               \
+                       "0:\tcmpxchgw %w2, %1"				      \
+		       : "=a" (ret), "=m" (*mem)			      \
+		       : "r" (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, %%gs:%P5\n\t"                                \
+                       "je 0f\n\t"                                            \
+                       "lock\n"                                               \
+                       "0:\tcmpxchgl %2, %1"				      \
+		       : "=a" (ret), "=m" (*mem)			      \
+		       : "r" (newval), "m" (*mem), "0" (oldval),	      \
+			 "i" (offsetof (tcbhead_t, multiple_threads)));	      \
+     ret; })
+
+/* 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.  */
+#if 1
+# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval)	      \
+  ({ __typeof (*mem) ret = *(mem);					      \
+     abort ();								      \
+     ret = (newval);							      \
+     ret = (oldval);							      \
+     ret; })
+# define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval)	      \
+  ({ __typeof (*mem) ret = *(mem);					      \
+     abort ();								      \
+     ret = (newval);							      \
+     ret = (oldval);							      \
+     ret; })
+#else
+# ifdef __PIC__
+#  define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+  ({ __typeof (*mem) ret;						      \
+     __asm __volatile ("xchgl %2, %%ebx\n\t"				      \
+		       LOCK_PREFIX "cmpxchg8b %1\n\t"			      \
+		       "xchgl %2, %%ebx"				      \
+		       : "=A" (ret), "=m" (*mem)			      \
+		       : "DS" (((unsigned long long int) (newval))	      \
+			       & 0xffffffff),				      \
+			 "c" (((unsigned long long int) (newval)) >> 32),     \
+			 "m" (*mem), "a" (((unsigned long long int) (oldval)) \
+					  & 0xffffffff),		      \
+			 "d" (((unsigned long long int) (oldval)) >> 32));    \
+     ret; })
+
+#  define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+  ({ __typeof (*mem) ret;						      \
+     __asm __volatile ("xchgl %2, %%ebx\n\t"				      \
+		       "cmpl $0, %%gs:%P7\n\t"				      \
+		       "je 0f\n\t"					      \
+		       "lock\n"						      \
+		       "0:\tcmpxchg8b %1\n\t"				      \
+		       "xchgl %2, %%ebx"				      \
+		       : "=A" (ret), "=m" (*mem)			      \
+		       : "DS" (((unsigned long long int) (newval))	      \
+			       & 0xffffffff),				      \
+			 "c" (((unsigned long long int) (newval)) >> 32),     \
+			 "m" (*mem), "a" (((unsigned long long int) (oldval)) \
+					  & 0xffffffff),		      \
+			 "d" (((unsigned long long int) (oldval)) >> 32),     \
+			 "i" (offsetof (tcbhead_t, multiple_threads)));	      \
+     ret; })
+# else
+#  define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+  ({ __typeof (*mem) ret;						      \
+     __asm __volatile (LOCK_PREFIX "cmpxchg8b %1"			      \
+		       : "=A" (ret), "=m" (*mem)			      \
+		       : "b" (((unsigned long long int) (newval))	      \
+			      & 0xffffffff),				      \
+			 "c" (((unsigned long long int) (newval)) >> 32),     \
+			 "m" (*mem), "a" (((unsigned long long int) (oldval)) \
+					  & 0xffffffff),		      \
+			 "d" (((unsigned long long int) (oldval)) >> 32));    \
+     ret; })
+
+#  define __arch_c_compare_and_exchange_val_64_acq(mem, newval, oldval) \
+  ({ __typeof (*mem) ret;						      \
+     __asm __volatile ("cmpl $0, %%gs:%P7\n\t"				      \
+		       "je 0f\n\t"					      \
+		       "lock\n"						      \
+		       "0:\tcmpxchg8b %1"				      \
+		       : "=A" (ret), "=m" (*mem)			      \
+		       : "b" (((unsigned long long int) (newval))	      \
+			      & 0xffffffff),				      \
+			 "c" (((unsigned long long int) (newval)) >> 32),     \
+			 "m" (*mem), "a" (((unsigned long long int) (oldval)) \
+					  & 0xffffffff),		      \
+			 "d" (((unsigned long long int) (oldval)) >> 32),     \
+			 "i" (offsetof (tcbhead_t, multiple_threads)));	      \
+     ret; })
+# endif
+#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								      \
+       {								      \
+	 result = 0;							      \
+	 abort ();							      \
+       }								      \
+     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								      \
+       {								      \
+	 __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 atomic_exchange_and_add(mem, value) \
+  __sync_fetch_and_add (mem, value)
+
+#define __arch_exchange_and_add_cprefix \
+  "cmpl $0, %%gs:%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, mem, value) \
+  do {									      \
+    if (__builtin_constant_p (value) && (value) == 1)			      \
+      atomic_increment (mem);						      \
+    else if (__builtin_constant_p (value) && (value) == -1)		      \
+      atomic_decrement (mem);						      \
+    else if (sizeof (*mem) == 1)					      \
+      __asm __volatile (lock "addb %b1, %0"				      \
+			: "=m" (*mem)					      \
+			: "iq" (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								      \
+      {									      \
+	__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);	      \
+      }									      \
+  } while (0)
+
+#define atomic_add(mem, value) \
+  __arch_add_body (LOCK_PREFIX, __arch, mem, value)
+
+#define __arch_add_cprefix \
+  "cmpl $0, %%gs:%P3\n\tje 0f\n\tlock\n0:\t"
+
+#define catomic_add(mem, value) \
+  __arch_add_body (__arch_add_cprefix, __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)		      \
+			 : "iq" (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								      \
+       abort ();							      \
+     __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)		      \
+			 : "iq" (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								      \
+       abort ();							      \
+     __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								      \
+      {									      \
+	__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 + 1, __oldval)) == __tmpval);		      \
+      }									      \
+  } while (0)
+
+#define atomic_increment(mem) __arch_increment_body (LOCK_PREFIX, __arch, mem)
+
+#define __arch_increment_cprefix \
+  "cmpl $0, %%gs:%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 %0; sete %b1"		      \
+			 : "=m" (*mem), "=qm" (__result)		      \
+			 : "m" (*mem));					      \
+     else if (sizeof (*mem) == 2)					      \
+       __asm __volatile (LOCK_PREFIX "incw %0; 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								      \
+       abort ();							      \
+     __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								      \
+      {									      \
+	__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 - 1, __oldval)) == __tmpval); 	      \
+      }									      \
+  } while (0)
+
+#define atomic_decrement(mem) __arch_decrement_body (LOCK_PREFIX, __arch, mem)
+
+#define __arch_decrement_cprefix \
+  "cmpl $0, %%gs:%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								      \
+       abort ();							      \
+     __result; })
+
+
+#define atomic_bit_set(mem, bit) \
+  do {									      \
+    if (sizeof (*mem) == 1)						      \
+      __asm __volatile (LOCK_PREFIX "orb %b2, %0"			      \
+			: "=m" (*mem)					      \
+			: "m" (*mem), "iq" (1 << (bit)));		      \
+    else if (sizeof (*mem) == 2)					      \
+      __asm __volatile (LOCK_PREFIX "orw %w2, %0"			      \
+			: "=m" (*mem)					      \
+			: "m" (*mem), "ir" (1 << (bit)));		      \
+    else if (sizeof (*mem) == 4)					      \
+      __asm __volatile (LOCK_PREFIX "orl %2, %0"			      \
+			: "=m" (*mem)					      \
+			: "m" (*mem), "ir" (1 << (bit)));		      \
+    else								      \
+      abort ();								      \
+  } 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), "ir" (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							      	      \
+       abort ();							      \
+     __result; })
+
+
+#define atomic_spin_nop() asm ("rep; nop")
+
+
+#define __arch_and_body(lock, mem, mask) \
+  do {									      \
+    if (sizeof (*mem) == 1)						      \
+      __asm __volatile (lock "andb %b1, %0"				      \
+			: "=m" (*mem)					      \
+			: "iq" (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								      \
+      abort ();								      \
+  } while (0)
+
+#define __arch_cprefix \
+  "cmpl $0, %%gs:%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)					      \
+			: "iq" (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								      \
+      abort ();								      \
+  } 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, (%%esp)" ::: "memory")
+#define atomic_read_barrier() __asm ("" ::: "memory")
+#define atomic_write_barrier() __asm ("" ::: "memory")