1 files changed, 61 insertions, 32 deletions

diff --git a/libpthread/linuxthreads/sysdeps/i386/pt-machine.h b/libpthread/linuxthreads/sysdeps/i386/pt-machine.h
index 82a5cf077..24c5e6c7c 100644
--- a/libpthread/linuxthreads/sysdeps/i386/pt-machine.h
+++ b/libpthread/linuxthreads/sysdeps/i386/pt-machine.h
@@ -18,17 +18,14 @@
    License along with the GNU C Library; see the file COPYING.LIB.  If
    not, see <http://www.gnu.org/licenses/>.  */
 
-#if defined __pentiumpro__ || defined __pentium4__ || defined __athlon__ || \
-	defined __k8__
-# include "i686/pt-machine.h"
-#else
-
 #ifndef _PT_MACHINE_H
 #define _PT_MACHINE_H	1
 
+#include <features.h>
+
 #ifndef __ASSEMBLER__
 #ifndef PT_EI
-# define PT_EI __extern_always_inline
+# define PT_EI __extern_always_inline __attribute__((visibility("hidden")))
 #endif
 
 extern long int testandset (int *spinlock);
@@ -39,6 +36,54 @@ extern int __compare_and_swap (long int *p, long int oldval, long int newval);
 #define CURRENT_STACK_FRAME  __builtin_frame_address (0)
 
 
+/* See if we can optimize for newer cpus... */
+#if defined __GNUC__ && __GNUC__ >= 2 && \
+   (defined __i486__ || defined __pentium__ || defined __pentiumpro__ || defined __pentium4__ || \
+    defined __athlon__ || defined __k8__)
+
+/* Spinlock implementation; required.  */
+PT_EI long int
+testandset (int *spinlock)
+{
+  long int ret;
+
+  __asm__ __volatile__ (
+	"xchgl %0, %1"
+	: "=r" (ret), "=m" (*spinlock)
+	: "0" (1), "m" (*spinlock)
+	: "memory");
+
+  return ret;
+}
+
+/* Compare-and-swap for semaphores.  It's always available on i686.  */
+#define HAS_COMPARE_AND_SWAP
+
+PT_EI int
+__compare_and_swap (long int *p, long int oldval, long int newval)
+{
+  char ret;
+  long int readval;
+
+  __asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
+			: "=q" (ret), "=m" (*p), "=a" (readval)
+			: "r" (newval), "m" (*p), "a" (oldval)
+			: "memory");
+  return ret;
+}
+
+#if defined(__ASSUME_LDT_WORKS) && __ASSUME_LDT_WORKS > 0
+#include "useldt.h"
+#endif
+
+/* The P4 and above really want some help to prevent overheating.  */
+#define BUSY_WAIT_NOP	__asm__ ("rep; nop")
+
+
+#else /* Generic i386 implementation */
+
+extern int compare_and_swap_is_available (void);
+
 /* Spinlock implementation; required.  */
 PT_EI long int
 testandset (int *spinlock)
@@ -75,43 +120,27 @@ __compare_and_swap (long int *p, long int oldval, long int newval)
   return ret;
 }
 
-
-PT_EI int get_eflags (void);
-PT_EI int
-get_eflags (void)
-{
-  int res;
-  __asm__ __volatile__ ("pushfl; popl %0" : "=r" (res) : );
-  return res;
-}
-
-
-PT_EI void set_eflags (int newflags);
-PT_EI void
-set_eflags (int newflags)
-{
-  __asm__ __volatile__ ("pushl %0; popfl" : : "r" (newflags) : "cc");
-}
-
-
-PT_EI int compare_and_swap_is_available (void);
 PT_EI int
 compare_and_swap_is_available (void)
 {
-  int oldflags = get_eflags ();
   int changed;
+  int oldflags;
+  /* get EFLAGS */
+  __asm__ __volatile__ ("pushfl; popl %0" : "=r" (oldflags) : );
   /* Flip AC bit in EFLAGS.  */
-  set_eflags (oldflags ^ 0x40000);
+  __asm__ __volatile__ ("pushl %0; popfl" : : "r" (oldflags ^ 0x40000) : "cc");
+  /* reread EFLAGS */
+  __asm__ __volatile__ ("pushfl; popl %0" : "=r" (changed) : );
   /* See if bit changed.  */
-  changed = (get_eflags () ^ oldflags) & 0x40000;
+  changed = (changed ^ oldflags) & 0x40000;
   /* Restore EFLAGS.  */
-  set_eflags (oldflags);
+  __asm__ __volatile__ ("pushl %0; popfl" : : "r" (oldflags) : "cc");
   /* If the AC flag did not change, it's a 386 and it lacks cmpxchg.
      Otherwise, it's a 486 or above and it has cmpxchg.  */
   return changed != 0;
 }
+#endif /* Generic i386 implementation */
+
 #endif /* __ASSEMBLER__ */
 
 #endif /* pt-machine.h */
-
-#endif