fix broken mips a_fetch_add

sc was overwriting the result

diff --git a/arch/mips/atomic.h b/arch/mips/atomic.h
index 33e53d4ed76e2841c588473c6d196640c096925c..a09f98df67d2c16a43491c063dce9071cc759214 100644 (file)
--- a/arch/mips/atomic.h
+++ b/arch/mips/atomic.h
@@ -70,19 +70,19 @@ static inline int a_swap(volatile int *x, int v)
 
 static inline int a_fetch_add(volatile int *x, int v)
 {
-       int new;
+       int old, dummy;
        __asm__ __volatile__(
                ".set push\n"
                ".set noreorder\n"
-               "1:     ll %0, 0(%1)\n"
-               "       addu %0, %0, %2\n"
-               "       sc %0, 0(%1)\n"
-               "       beq %0, $0, 1b\n"
+               "1:     ll %0, 0(%2)\n"
+               "       addu %1, %0, %3\n"
+               "       sc %1, 0(%2)\n"
+               "       beq %1, $0, 1b\n"
                "       nop\n"
                "1:     \n"
                ".set pop\n"
-               : "=&r"(new) : "r"(x), "r"(v) : "memory" );
-        return new-v;
+               : "=&r"(old), "=&r"(dummy) : "r"(x), "r"(v) : "memory" );
+        return old;
 }
 
 static inline void a_inc(volatile int *x)