Changeset 7637 in vbox

Timestamp:

Mar 28, 2008 6:48:06 PM (17 years ago)

Author:

vboxsync

Message:

cmpxchgl may change eax on failure, so tell the compiler that it output as well as input. (This was the cause of the ATA thread problems (exited because of timeout from rtSemEventWait).)

File:

• trunk/include/iprt/asm.h (modified) (1 diff)

trunk/include/iprt/asm.h

@@ -2197 +2197 @@
 DECLASM(bool) ASMAtomicCmpXchgU32(volatile uint32_t *pu32, const uint32_t u32New, const uint32_t u32Old);
 #else
-DECLINLINE(bool) ASMAtomicCmpXchgU32(volatile uint32_t *pu32, const uint32_t u32New, const uint32_t u32Old)
+DECLINLINE(bool) ASMAtomicCmpXchgU32(volatile uint32_t *pu32, const uint32_t u32New, uint32_t u32Old)
 {
 # if RT_INLINE_ASM_GNU_STYLE
     uint8_t u8Ret;
-    __asm__ __volatile__("lock; cmpxchgl %2, %0\n\t"
+    __asm__ __volatile__("lock; cmpxchgl %3, %0\n\t"
                          "setz  %1\n\t"
                          : "=m" (*pu32),
-                           "=qm" (u8Ret)
+                           "=qm" (u8Ret),
+                           "=a" (u32Old)
                          : "r" (u32New),
-                           "a" (u32Old));
+                           "2" (u32Old));
     return (bool)u8Ret;