Ticket #1575: patch-mutex.h

--- include/mutex.h.orig        2001-05-06 21:19:20.000000000 +0800
+++ include/mutex.h     2004-02-13 06:18:17.000000000 +0800
@@ -482,6 +482,31 @@
  * 'set' mutexes have the value 1, like on Intel; the returned value from
  * MUTEX_SET() is 1 if the mutex previously had its low bit clear, 0 otherwise.
  */
+#if defined(__APPLE__) && defined(__MACH__) && defined(__ppc__)
+#warning "Using apple specific mutexes" 
+extern int __db_mutex_set __P((volatile tsl_t *));
+void
+__db_mutex_tas_dummy()
+{
+       __asm__ __volatile__("          \n\
+       .globl  ___db_mutex_set         \n\
+___db_mutex_set:                       \n\
+       lwarx   r5,0,r3                 \n\
+       cmpwi   r5,0                    \n\
+       bne     fail                    \n\
+       addi    r5,r5,1                 \n\
+       stwcx.  r5,0,r3                 \n\
+       beq     success                 \n\
+fail:                                  \n\
+       li      r3,0                    \n\
+       blr                             \n\
+success:                               \n\
+       li      r3,1                    \n\
+       blr");  
+}
+#define        MUTEX_SET(tsl)  __db_mutex_set(tsl)
+#else
+ 
 #define        MUTEX_SET(tsl)  ({              \
        int __one = 1;                  \
        int __r;                        \
@@ -499,6 +524,7 @@
        !(__r & 1);                     \
 })
 
+#endif
 #define        MUTEX_UNSET(tsl)        (*(tsl) = 0)
 #define        MUTEX_INIT(tsl)         MUTEX_UNSET(tsl)
 #endif