X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fx86-arch.h;h=582bfc7e016b668ee47b33285b5eecea099e36b9;hb=43c6634142a96e1d1bab2efe1a39cd8234903c41;hp=2dfac4792afe40f9c41a11107667e5e2a6c7706b;hpb=59f4a9f62d1ab9656b02eef240d7aac65669262d;p=sbcl.git

diff --git a/src/runtime/x86-arch.h b/src/runtime/x86-arch.h
index 2dfac47..582bfc7 100644
--- a/src/runtime/x86-arch.h
+++ b/src/runtime/x86-arch.h
@@ -18,7 +18,19 @@
  * here? (The answer wasn't obvious to me when merging the
  * architecture-abstracting patches for CSR's SPARC port. -- WHN 2002-02-15) */
 
-#include "interr.h"
+#define COMPILER_BARRIER \
+    do { __asm__ __volatile__ ( "" : : : "memory"); } while (0)
+
+#ifdef LISP_FEATURE_WIN32
+extern int os_number_of_processors;
+#define yield_on_uniprocessor()                 \
+    do { if (os_number_of_processors<=1) SwitchToThread(); } while(0)
+#else
+/* Stubs are better than ifdef EVERYWHERE. */
+#define yield_on_uniprocessor()                 \
+    do {} while(0)
+#endif
+
 
 static inline void
 get_spinlock(volatile lispobj *word, unsigned long value)
@@ -35,20 +47,30 @@ get_spinlock(volatile lispobj *word, unsigned long value)
              : "r" (value), "m" (*word)
              : "memory", "cc");
 #else
+        if (eax!=0) {
+            asm volatile("rep; nop");
+        }
         asm volatile ("xor %0,%0\n\
               lock cmpxchg %1,%2"
              : "=a" (eax)
              : "r" (value), "m" (*word)
              : "memory", "cc");
 #endif
-
+        yield_on_uniprocessor();
     } while(eax!=0);
 #else
     *word=value;
 #endif
 }
 
-#include <stdio.h>
+static inline void
+release_spinlock(volatile lispobj *word)
+{
+    /* See comment in RELEASE-SPINLOCK in target-thread.lisp. */
+    COMPILER_BARRIER;
+    *word=0;
+    COMPILER_BARRIER;
+}
 
 static inline lispobj
 swap_lispobjs(volatile lispobj *dest, lispobj value)
@@ -68,14 +90,6 @@ swap_lispobjs(volatile lispobj *dest, lispobj value)
     return old_value;
 }
 
-static inline void
-release_spinlock(volatile lispobj *word)
-{
-    /* A memory barrier is needed, use swap_lispobjs. See comment in
-     * RELEASE-SPINLOCK in target-thread.lisp. */
-    swap_lispobjs(word,0);
-}
-
 extern void fast_bzero_detect(void *, size_t);
 extern void (*fast_bzero_pointer)(void *, size_t);