1 files changed, 103 insertions, 0 deletions
diff --git a/include/asm-alpha/atomic.h b/include/asm-alpha/atomic.h
new file mode 100644
index 000000000..621c3a932
--- /dev/null
+++ b/include/asm-alpha/atomic.h
@@ -0,0 +1,103 @@
+#ifndef __ARCH_ALPHA_ATOMIC__
+#define __ARCH_ALPHA_ATOMIC__
+
+/*
+ * Atomic operations that C can't guarantee us.  Useful for
+ * resource counting etc...
+ *
+ * But use these as seldom as possible since they are much more slower
+ * than regular operations.
+ */
+
+/*
+ * Make sure gcc doesn't try to be clever and move things around
+ * on us. We need to use _exactly_ the address the user gave us,
+ * not some alias that contains the same information.
+ */
+#define __atomic_fool_gcc(x) (*(struct { int a[100]; } *)x)
+
+typedef int atomic_t;
+
+extern __inline__ void atomic_add(atomic_t i, atomic_t * v)
+{
+	unsigned long temp;
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldl_l %0,%1\n\t"
+		"addl %0,%2,%0\n\t"
+		"stl_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (__atomic_fool_gcc(v))
+		:"Ir" (i),
+		 "m" (__atomic_fool_gcc(v)));
+}
+
+extern __inline__ void atomic_sub(atomic_t i, atomic_t * v)
+{
+	unsigned long temp;
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldl_l %0,%1\n\t"
+		"subl %0,%2,%0\n\t"
+		"stl_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (__atomic_fool_gcc(v))
+		:"Ir" (i),
+		 "m" (__atomic_fool_gcc(v)));
+}
+
+/*
+ * Same as above, but return the result value
+ */
+extern __inline__ long atomic_add_return(atomic_t i, atomic_t * v)
+{
+	long temp, result;
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldl_l %0,%1\n\t"
+		"addl %0,%3,%0\n\t"
+		"bis %0,%0,%2\n\t"
+		"stl_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (__atomic_fool_gcc(v)),
+		 "=&r" (result)
+		:"Ir" (i),
+		 "m" (__atomic_fool_gcc(v)));
+	return result;
+}
+
+extern __inline__ long atomic_sub_return(atomic_t i, atomic_t * v)
+{
+	long temp, result;
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldl_l %0,%1\n\t"
+		"subl %0,%3,%0\n\t"
+		"bis %0,%0,%2\n\t"
+		"stl_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (__atomic_fool_gcc(v)),
+		 "=&r" (result)
+		:"Ir" (i),
+		 "m" (__atomic_fool_gcc(v)));
+	return result;
+}
+
+#define atomic_dec_return(v) atomic_sub_return(1,(v))
+#define atomic_inc_return(v) atomic_add_return(1,(v))
+
+#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
+#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
+
+#define atomic_inc(v) atomic_add(1,(v))
+#define atomic_dec(v) atomic_sub(1,(v))
+
+#endif