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Date:      Mon, 7 Mar 2005 19:39:01 GMT
From:      John Baldwin <jhb@FreeBSD.org>
To:        Perforce Change Reviews <perforce@freebsd.org>
Subject:   PERFORCE change 72647 for review
Message-ID:  <200503071939.j27Jd1sN012921@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=72647

Change 72647 by jhb@jhb_slimer on 2005/03/07 19:38:05

	- List memory addresses as both an input and an output rather than
	  using the + modifier with memory operands.
	- Use alpha_wmb() rather than alpha_mb() for rel variants.
	- Don't clobbery memory in each atomic op but only do it for acq
	  variants.
	- Move the membar for acq variants before the operation. (This
	  probably has no affect, but I think this is more correct.)

Affected files ...

.. //depot/projects/smpng/sys/alpha/include/atomic.h#10 edit

Differences ...

==== //depot/projects/smpng/sys/alpha/include/atomic.h#10 (text+ko) ====

@@ -53,12 +53,11 @@
 #ifdef __GNUC__
 	__asm __volatile (
 		"1:\tldl_l %0, %2\n\t"		/* load old value */
-		"bis %0, %3, %0\n\t"		/* calculate new value */
+		"bis %0, %2, %0\n\t"		/* calculate new value */
 		"stl_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
 		: "=&r" (temp), "=m" (*p)
-		: "m" (*p), "r" (v)
-		: "memory");
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -72,9 +71,8 @@
 		"bic %0, %2, %0\n\t"		/* calculate new value */
 		"stl_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -88,9 +86,8 @@
 		"addl %0, %2, %0\n\t"		/* calculate new value */
 		"stl_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -104,9 +101,8 @@
 		"subl %0, %2, %0\n\t"		/* calculate new value */
 		"stl_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -121,9 +117,8 @@
 		"ldiq %1,0\n\t"		/* value to store */
 		"stl_c %1,%2\n\t"	/* attempt to store */
 		"beq %1,1b\n"		/* if the store failed, spin */
-		: "=&r"(result), "=&r"(temp), "+m" (*addr)
-		:
-		: "memory");
+		: "=&r"(result), "=&r"(temp), "=m" (*addr)
+		: "m" (*addr));
 #endif
 
 	return result;
@@ -139,9 +134,8 @@
 		"bis %0, %2, %0\n\t"		/* calculate new value */
 		"stq_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -155,9 +149,8 @@
 		"bic %0, %2, %0\n\t"		/* calculate new value */
 		"stq_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -171,9 +164,8 @@
 		"addq %0, %2, %0\n\t"		/* calculate new value */
 		"stq_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -187,9 +179,8 @@
 		"subq %0, %2, %0\n\t"		/* calculate new value */
 		"stq_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n"			/* spin if failed */
-		: "=&r" (temp), "+m" (*p)
-		: "r" (v)
-		: "memory");
+		: "=&r" (temp), "=m" (*p)
+		: "r" (v), "m" (*p));
 #endif
 }
 
@@ -205,8 +196,7 @@
 		"stq_c %1,%2\n\t"	/* attempt to store */
 		"beq %1,1b\n"		/* if the store failed, spin */
 		: "=&r"(result), "=&r"(temp), "+m" (*addr)
-		:
-		: "memory");
+		: "m" (*addr));
 #endif
 
 	return result;
@@ -238,28 +228,30 @@
 static __inline void							\
 atomic_##NAME##_acq_##WIDTH(volatile u_int##WIDTH##_t *p, u_int##WIDTH##_t v)\
 {									\
+	alpha_mb(); 							\
+	__asm __volatile("" ::: "memory");				\
 	atomic_##NAME##_##WIDTH(p, v);					\
-	alpha_mb(); 							\
 }									\
 									\
 static __inline void							\
 atomic_##NAME##_rel_##WIDTH(volatile u_int##WIDTH##_t *p, u_int##WIDTH##_t v)\
 {									\
-	alpha_mb();							\
+	alpha_wmb();							\
 	atomic_##NAME##_##WIDTH(p, v);					\
 }									\
 									\
 static __inline void							\
 atomic_##NAME##_acq_##TYPE(volatile u_int##WIDTH##_t *p, u_int##WIDTH##_t v)\
 {									\
+	alpha_mb();							\
+	__asm __volatile("" ::: "memory");				\
 	atomic_##NAME##_##WIDTH(p, v);					\
-	alpha_mb();							\
 }									\
 									\
 static __inline void							\
 atomic_##NAME##_rel_##TYPE(volatile u_int##WIDTH##_t *p, u_int##WIDTH##_t v)\
 {									\
-	alpha_mb();							\
+	alpha_wmb();							\
 	atomic_##NAME##_##WIDTH(p, v);					\
 }
 
@@ -291,31 +283,34 @@
 {							\
 	u_##TYPE v;					\
 							\
+	alpha_mb();					\
+	__asm __volatile("" ::: "memory");		\
 	v = *p;						\
-	alpha_mb();					\
 	return (v);					\
 }							\
 							\
 static __inline void					\
 atomic_store_rel_##WIDTH(volatile u_##TYPE *p, u_##TYPE v)\
 {							\
-	alpha_mb();					\
+	alpha_wmb();					\
 	*p = v;						\
 }							\
+							\
 static __inline u_##TYPE				\
 atomic_load_acq_##TYPE(volatile u_##TYPE *p)		\
 {							\
 	u_##TYPE v;					\
 							\
+	alpha_mb();					\
+	__asm __volatile("" ::: "memory");		\
 	v = *p;						\
-	alpha_mb();					\
 	return (v);					\
 }							\
 							\
 static __inline void					\
 atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
 {							\
-	alpha_mb();					\
+	alpha_wmb();					\
 	*p = v;						\
 }
 
@@ -345,9 +340,8 @@
 		"stl_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n\t"		/* if it failed, spin */
 		"2:\n"
-		: "=&r" (ret), "+m" (*p)
-		: "r" ((long)(int)cmpval), "r" (newval)
-		: "memory");
+		: "=&r" (ret), "=m" (*p)
+		: "r" ((long)(int)cmpval), "r" (newval), "m" (*p));
 #endif
 
 	return ret;
@@ -372,9 +366,8 @@
 		"stq_c %0, %1\n\t"		/* attempt to store */
 		"beq %0, 1b\n\t"		/* if it failed, spin */
 		"2:\n"
-		: "=&r" (ret), "+m" (*p)
-		: "r" (cmpval), "r" (newval)
-		: "memory");
+		: "=&r" (ret), "=m" (*p)
+		: "r" (cmpval), "r" (newval), "m" (*p));
 #endif
 
 	return ret;
@@ -396,15 +389,16 @@
 {
 	int retval;
 
+	alpha_mb();
+	__asm __volatile("" ::: "memory");
 	retval = atomic_cmpset_32(p, cmpval, newval);
-	alpha_mb();
 	return (retval);
 }
 
 static __inline u_int32_t
 atomic_cmpset_rel_32(volatile u_int32_t *p, u_int32_t cmpval, u_int32_t newval)
 {
-	alpha_mb();
+	alpha_wmb();
 	return (atomic_cmpset_32(p, cmpval, newval));
 }
 
@@ -413,15 +407,16 @@
 {
 	int retval;
 
+	alpha_mb();
+	__asm __volatile("" ::: "memory");
 	retval = atomic_cmpset_64(p, cmpval, newval);
-	alpha_mb();
 	return (retval);
 }
 
 static __inline u_int64_t
 atomic_cmpset_rel_64(volatile u_int64_t *p, u_int64_t cmpval, u_int64_t newval)
 {
-	alpha_mb();
+	alpha_wmb();
 	return (atomic_cmpset_64(p, cmpval, newval));
 }

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