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+/*
+ * @(#)sparc.gcc	10.1 (Sleepycat) 4/12/97
+ *
+ * The ldstub instruction takes the location specified by its first argument
+ * (a register containing a memory address) and loads its contents into its
+ * second argument (a register) and atomically sets the contents the location
+ * specified by its first argument to a byte of 1s.  (The value in the second
+ * argument is never read, but only overwritten.)
+ *
+ * The membar instructions are needed to ensure that writes to the lock are
+ * correctly ordered with writes that occur later in the instruction stream.
+ *
+ * For gcc/sparc, 0 is clear, 1 is set.
+ */
+
+#if defined(__sparcv9__)
+Does the following code need membar instructions for V9 processors?
+#endif
+
+#define	TSL_SET(tsl) ({							\
+	register tsl_t *__l = (tsl);					\
+	register tsl_t __r;						\
+	__asm__ volatile						\
+	    ("ldstub [%1],%0"						\
+	    : "=r"( __r) : "r" (__l));					\
+	!__r;								\
+})
+
+#define	TSL_UNSET(tsl) ({						\
+         register tsl_t *__l = (tsl);					\
+        __asm__ volatile ("stb %%g0,[%0]" : : "r" (__l));		\
+})
+#define	TSL_INIT(tsl)	TSL_UNSET(tsl)