X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fx86-arch.h;h=582bfc7e016b668ee47b33285b5eecea099e36b9;hb=5f0bd05a15aaf93f46baf9b8aa3e9b0bfbca26ab;hp=1a51e6b43162bab7a7279071ac756af84b5bd4cd;hpb=4d633465231c79adeb3e4e59bf30c011d1d0e9dd;p=sbcl.git

diff --git a/src/runtime/x86-arch.h b/src/runtime/x86-arch.h
index 1a51e6b..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)
@@ -35,13 +47,16 @@ 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;
@@ -51,11 +66,12 @@ get_spinlock(volatile lispobj *word, unsigned long value)
 static inline void
 release_spinlock(volatile lispobj *word)
 {
+    /* See comment in RELEASE-SPINLOCK in target-thread.lisp. */
+    COMPILER_BARRIER;
     *word=0;
+    COMPILER_BARRIER;
 }
 
-#include <stdio.h>
-
 static inline lispobj
 swap_lispobjs(volatile lispobj *dest, lispobj value)
 {