Changeset 1488 for trunk/src/emx/include/386/builtin.h

Timestamp:

Sep 10, 2004, 9:39:57 AM (21 years ago)

Author:

bird

Message:

Going to bed. something is still broken.

File:

• trunk/src/emx/include/386/builtin.h (modified) (1 diff, 1 prop)

trunk/src/emx/include/386/builtin.h

@@ -299 +299 @@
 
 
+/**
+ * Atomically compare and exchange a 32-bit word.
+ *
+ * @returns 1 if changed, 0 if unchanged (i.e. boolean).
+ * @param   pu32    Pointer to the value to compare & exchange.
+ * @param   u32New  The new value.
+ * @param   u32Cur  The current value. Only update if *pu32 equals this one.
+ */
+static inline unsigned __atomic_cmpxchg32(volatile uint32_t *pu32, uint32_t u32New, uint32_t u32Old)
+{
+    __asm__ __volatile__("lock  cmpxchgl %2, %1\n\t"
+                         "setz  %%al\n\t"
+                         "movzx %%al, %%eax\n\t"
+                         : "=a" (u32Old),
+                           "=m" (*pu32)
+                         : "r"  (u32New),
+                           "0" (u32Old));
+    return (unsigned)u32Old;
+}
+
+
 #define __ROTATE_FUN(F,I,T) \
   static __inline__ T F (T value, int shift) \