Update.

2003-03-20  Ulrich Drepper  <drepper@redhat.com>

	* include/atomic.h: Define atomic_exchange and
	atomic_decrement_if_positive if not already defined.  Add some
	__builtin_expect.
	* sysdeps/i386/i486/bits/atomic.h: Define atomic_exchange.
	* sysdeps/x86_64/bits/atomic.h: Likewise.
	* sysdeps/ia64/bits/atomic.h: Pretty printing.  Define atomic_exchange.
	* sysdeps/powerpc/bits/atomic.h: Pretty printing.  Define
	atomic_exchange, atomic_exchange_and_add, and
	atomic_decrement_if_positive

ChangeLog

@@ -1,3 +1,15 @@
+2003-03-20  Ulrich Drepper  <drepper@redhat.com>
+
+	* include/atomic.h: Define atomic_exchange and
+	atomic_decrement_if_positive if not already defined.  Add some
+	__builtin_expect.
+	* sysdeps/i386/i486/bits/atomic.h: Define atomic_exchange.
+	* sysdeps/x86_64/bits/atomic.h: Likewise.
+	* sysdeps/ia64/bits/atomic.h: Pretty printing.  Define atomic_exchange.
+	* sysdeps/powerpc/bits/atomic.h: Pretty printing.  Define
+	atomic_exchange, atomic_exchange_and_add, and
+	atomic_decrement_if_positive
+
 2003-03-20  Alexandre Oliva  <aoliva@redhat.com>
 
 	* sysdeps/unix/sysv/linux/mips/mips64/n64/ioctl.S: Sign-extend

sysdeps/i386/i486/bits/atomic.h

@@ -119,6 +119,29 @@ typedef uintmax_t uatomic_max_t;
 #endif
 
 
+/* Note that we need no lock prefix.  */
+#define atomic_exchange(mem, newvalue) \
+  ({ __typeof (*mem) result;						      \
+     if (sizeof (*mem) == 1)						      \
+       __asm __volatile ("xchgb %b0, %1"				      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else if (sizeof (*mem) == 2)					      \
+       __asm __volatile ("xchgw %w0, %1"				      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else if (sizeof (*mem) == 4)					      \
+       __asm __volatile ("xchgl %0, %1"					      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else								      \
+       {								      \
+	 result = 0;							      \
+	 abort ();							      \
+       }								      \
+     result; })
+
+
 #define atomic_exchange_and_add(mem, value) \
   ({ __typeof (*mem) result;						      \
      __typeof (value) addval = (value);					      \

sysdeps/ia64/bits/atomic.h

@@ -67,6 +67,10 @@ typedef uintmax_t uatomic_max_t;
   __sync_val_compare_and_swap_di ((long *) (mem), (long) (oldval), \
 				  (long) (newval))
 
+/* Atomically store newval and return the old value.  */
+#define atomic_exchange(mem, value) \
+  __sync_lock_test_and_set_si (mem, value)
+
 #define atomic_exchange_and_add(mem, value) \
   ({									      \
     __typeof (*mem) __oldval, __val;					      \

sysdeps/powerpc/bits/atomic.h

@@ -107,6 +107,56 @@ typedef uintmax_t uatomic_max_t;
   (abort (), 0)
 #endif
 
+
+#define atomic_exchange(mem, value) \
+  ({ if (sizeof (*mem) != 4)						      \
+       abort ();							      \
+     int __val, __tmp;							      \
+      __asm __volatile (__ARCH_REL_INSTR "\n"				      \
+			"1:	lwarx	%0,0,%2\n"			      \
+			"	stwcx.	%3,0,%2\n"			      \
+			"	bne-	1b"				      \
+			: "=&r" (__val), "=m" (*mem)			      \
+			: "r" (mem), "r" (value), "1" (*mem)		      \
+			: "cr0", "memory");				      \
+      __val; })
+
+
+#define atomic_exchange_and_add(mem, value) \
+  ({ if (sizeof (*mem) != 4)						      \
+       abort ();							      \
+     int __val, __tmp;							      \
+     __asm __volatile ("1:	lwarx	%0,0,%3\n"			      \
+		       "	addi	%1,%0,%4\n"			      \
+		       "	stwcx.	%1,0,%3\n"			      \
+		       "	bne-	1b"				      \
+		       : "=&b" (__val), "=&r" (__tmp), "=m" (*mem)	      \
+		       : "r" (mem), "I" (value), "2" (*mem)		      \
+		       : "cr0");					      \
+     __val;								      \
+  })
+
+
+/* Decrement *MEM if it is > 0, and return the old value.  */
+#define atomic_decrement_if_positive(mem) \
+  ({ if (sizeof (*mem) != 4)						      \
+       abort ();							      \
+     int __val, __tmp;							      \
+     __asm __volatile ("1:	lwarx	%0,0,%3\n"			      \
+		       "	cmpwi	0,%0,0\n"			      \
+		       "	addi	%1,%0,-1\n"			      \
+		       "	ble	2f\n"				      \
+		       "	stwcx.	%1,0,%3\n"			      \
+		       "	bne-	1b\n"				      \
+		       "2:	" __ARCH_ACQ_INSTR			      \
+		       : "=&b" (__val), "=&r" (__tmp), "=m" (*mem)	      \
+		       : "r" (mem), "2" (*mem)				      \
+		       : "cr0");					      \
+     __val;								      \
+  })
+
+
+
 #define atomic_full_barrier()	__asm ("sync" ::: "memory")
 #ifdef __powerpc64__
 # define atomic_read_barrier()	__asm ("lwsync" ::: "memory")

sysdeps/x86_64/bits/atomic.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2002 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -84,6 +84,28 @@ typedef uintmax_t uatomic_max_t;
      ret; })
 
 
+/* Note that we need no lock prefix.  */
+#define atomic_exchange(mem, newvalue) \
+  ({ __typeof (*mem) result;						      \
+     if (sizeof (*mem) == 1)						      \
+       __asm __volatile ("xchgb %b0, %1"				      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else if (sizeof (*mem) == 2)					      \
+       __asm __volatile ("xchgw %w0, %1"				      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else if (sizeof (*mem) == 4)					      \
+       __asm __volatile ("xchgl %0, %1"					      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     else								      \
+       __asm __volatile ("xchgq %q0, %1"				      \
+			 : "=r" (result), "=m" (*mem)			      \
+			 : "0" (newvalue), "1" (*mem));			      \
+     result; })
+
+
 #define atomic_exchange_and_add(mem, value) \
   ({ __typeof (*mem) result;						      \
      if (sizeof (*mem) == 1)						      \